With any of the 88-key workstations:
They consume a fair amount of physical space... and they weigh about 60 pounds (+/-).
 
My dilemma with Kronos is that I don't use it anywhere near its full potential.
Back in the 90s, almost everything I did was keyboard based... and was more jazz/fusion/prog inspired.
As an old man , I'm more into stripped down rock (drums, bass, guitar, vocals).
That space and investment could go toward other things...

I agree that a person with Sonar and a good sample player probably doesn't need a Kronos.
 
Remember back in the day when it was cool to have three or four hardware keyboards on A stands in your studio? In reality we can now have 100's of virtual keyboards in our computers. From the outside it might not look like much. Looses some of the cool factor. Now it's similar to an old car collector who never drives the cars. Old hardware can sit and collect dust.
 
Playing rock music really only needs a few elements, so yeah I can sure see why the Kronos is overkill for you as well. I'm in a similar situation. Most of the sounds in romplers and hardware synths I like to play for the enjoyment of listening to the sound, but those sounds won't ever make it into most of my mixes. Pad sounds are probably the worst for me personally and this seems to be what is in the soundbanks of most keyboards aside from the tried and true basic sounds.Pads and "evolving textures" are about 90% of the sounds, especially in the Korgs.
I might use 1% of those for light backing set 12 db in the mix occasionally. But to each his or her own. Omnisphere kinds of sounds don't see much use here.
 
Maybe this is more about the nostalgia of it for me. Taking an audio output from a keyboard into a mixer takes me back to the old days. Something about how well that works compared to some soft synths is enough for me to want at least a hardware keyboard or two laying around.
 
Another thing is, there aren't any software renewals or updates. As long as the hardware lasts is how long you'll have those sounds no matter what happens to your computer.
 
My M-audio 88ex weighs just 17 pounds. The Kronos can't compete with that, but it sure would make a nice paper weight to have around the studio :)
 
 

Some of those older Yamaha, Korg, or Roland work stations like a Fantom with a few expansions in are good value. 
 
The Kurzweil has a nice sequencer and it is easy to assign sounds to tracks and get under way jotting down ideas if you are away from the studio.
 
Kurzweil songs can be exported as midi files and easily imported into the DAW. You can get the DAW to send a midi clock and sync the sequencer if you wanted to transfer the audio of your ideas across to your DAW.  I don't use the sequencer much as it is in my studio acting as a controller and its internal sound engine being addressed from Studio One instead.
 
There are 9 faders on the front panel which can be used as controllers for your DAW and they are assigned also to the internal patches/effects making quite a few edits to parameter changes possbible very easily. VAST is very deep and you can get right into the programming side of it too, if you want or just use its huge sound library as it is for a lot of music making. It also has a ribbon input, inputs for controllers including the Yamaha breath controller.
 
The many sounds are organised into categories so they are easy to navigate to fast and fine stuff.  It boots up pretty quickly I think compared to a Kronos. 
 
Some things few know as well. The Kurzweil also has the KB3 organ emulation inside it too and also a third instrument called the VA1. This was a massive hardware synth that used analog modeling to be a very nice analog sounding instrument.  It never took off.  (eg very similar to Novation Supernova which I really like the sound of)  They have incorporated the VA1 inside the PC3K. So it is a serious sounding fat analog synth as well.  So in a way there are three synth engines built in.
 
Kronos is a fabulous instrument too. The 9 synth engines are all excellent and can be used at once. All Korg instruments of this quality sound excellent. The Kurzwiel is also sheer class in the power and depth of sound department.  They have an all new sample library for the PC3K series.  Lovely stereo sampling being done.  It sounds better to me than the older K2000 which also sounds great too. The latest models are the best sounding Kurzweils I have ever heard.  I know I am biased.  I have loved them for a long time!
 

I've had an older Yamaha motif and a few of the older Korg keyboards and Roland. Played with an old Ensoniq Mirage. Never had the opportunity to try a Kurzweil. Give me too many choices and I can't make a decision on anything haha...but now you've got my curiosity up Jeff. 
 
Didn't that company change hands and almost go under? It seems I remember years ago when I was looking to purchase a keyboard Kurzweil was in transition as a company. This was why I didn't look at them too hard. I wasn't sure how long they would be around.
 
There's also some incredible accompaniment synths that don't get much press. Korg makes the PA4x ( I might have gotten that wrong) It looks loaded well for a solo act. Yamaha has the Tyros which is supposed to be good. How about Wersi? Ever play a Wersi? http://wersimusic.com/newproducts/pegasus-wing/
 
Many of these boards likely have similar soundsets to their rompler playing workstation cousins. My first impressions of accompaniment were that they can sound cheesy and fake, especially if you try to pull off that electric guitar solo on the keys :) I had a mid level Yamaha PSR at one time. It did some things ok, but others it didn't. The more recent better accompaniment keyboards are in another league, but I haven't personally demoed them. I heard examples on the web.
 
 
 

Here's what I think:  If your primary use is in the studio, and you have loads of VST samples, you may find that a workstation is overkill, for sure.  If you also want to take it on gigs, then size and weight are major factors, IMO. If you play a lot more piano than other types of keys (organs, synths, etc.) then the fully weighted keyboard is the way to go. If I'm describing all this for you, it's clear that this is how I approach it. Since I play more piano than anything, the full keyboard with fully weighted keys is a must. After years and years of this, my setup is evolving as I write this. I've been a Roland guy for many years, and still use my RD-300 GX as my studio controller. It's onboard sounds are still not bad, but I only use a few of them, mostly just piano and epiano. I also have lots of VST's for my studio work. The real problem was that even though the RD 300 has somewhat low weight of 36 pounds, it's getting harder and harder for me to lug it around, and discourages my wanting to play out. I now have a Roland VR09 as a 2nd keyboard, and this little baby is so useful for the onboard sounds it produces, especially the synths and organs. It's only 61 keys and has synth touch, perfect for what I use it for. It's so light that it's almost an afterthought to carry.
So my holy grail was to find a lighter 88 key fully-weighted stage piano, and after considering the Nord Stage 2 HP 76, which is from 3-4K and above (with 76 keys and a "lighter" hammer action bed), I discovered a newer player, and that is why I now have a Casio PX-5S. 24 pounds! Nice keyboard, 88 keys, fully weighted, a joy to play. Onboard sounds are great, and there are a zillion of them, all fully editable, etc. Computer connectivity, full MIDI implementation, etc., etc. etc. Having now used it on a gig, I am hooked. No more broken back, I can carry it on one arm. Could double as a studio controller due to it's versatility and using it with VST's etc., also works. But now I have the Roland RD 300 as a dedicated studio controller, and the Casio and Vr09 for gigging, etc. No more breaking down and setting up from studio to the road. And the Casio has a lot of knobs and sliders for realtime control of almost anything, fully configurable by the user, too, including stage setups for quick recall, etc. I have only started to learn about it. And it's price is 2/3 less than the Nord (and the Kronos, too). 
I urge you to at least stop laughing at the brand name and consider this keyboard, too. You'll save a ton of money and your back will thank you. I've been a pro player for more years than most, and I swear to you this is a high quality professional product that the most demanding pianists/keyboardists would find appealing and useful, and a bargain. For way less than a Kronos, you could have the VR09 and the PX5S and pretty much cover all the bases. Check it out here.
That is all.

Thanks for those recommendations Dave! I checked out your music. Great stuff!
 
I actually have a Privia 150 ( I think).  I love the feel of the weighted keys. The piano sound is very nice. It would be great for a small quiet gig since it has internal speakers.It has usb midi, but I didn't like the usb midi and would rather use 5 pin midi into my audio interface. Another minus for it was it only had a TRS audio output. If the PX5s has this keybed, then I know I would like the feel of it. I fell behind on the more recent Casio gear so I appreciate that you pointed this keyboard out to me. I looked at a few demos and I'm impressed. I could probably go demo one of these at GC if management can keep the 14 year old plinkers off for awhile.
 
I work similar to you only I don't  take a keyboard out since I've been playing as a weekly church pianist for over 15 years. They have a Schimmel Grand. 
The only time I really need to carry a separate keyboard out is when they have a picnic and the last time I took an acoustic guitar instead.Was a lot easier in that case. The last time I needed to use a keyboard out was playing a funeral...yeah you heard right, a funeral. The third one I've done. 
When I play in bars I'm on a different instrument.
 
My studio needs are fairly simple. I usually track both a midi track and the audio from the keyboard, so a prime consideration for me in the studio is I don't want honky midi. Whatever I use I need it to track and output midi accurately. My M-audio board occasionally hiccups with the sustain pedal during a midi recording. Having the most layers of midi velocity sensitivity is another big one for me. Soft pedal would be a nice addition.
I then take the midi track and use it with a soft synth, usually a decent vst piano.
 
The onboard sounds come in handy for me because in the morning before my piano gig I'll pull a music set and I might want to practice a piece without the computer. It's nice to simply turn it on and play. I'm usually pushed for time and in a hurry to get out the door. No time to boot a computer.
 
For several years I was taking a board to a portable gig every week and that's when I bought the M-audio 88sx. The Roland Juno Stage 76 key was also fairly lightweight. It would be nice to know that the Casio PX5S is so lightweight, especially for an old guy like me ;)
 

Thanks for the kind words, Starwise.  BTW, The PX5S has both usb midi AND 5 pin Midi functionality. Pedal functionality might be more limited in some ways, but Casio now also has a PX560 (I think that's the number) with slightly improved pedal inputs and also a touch screen interface. I preferred the PX5's sliders and knobs, and their Stage Setups vs. "Registrations" inplementation. YMMV, of course. The combo of light weight, weighted full keybed, full MIDI (I use my Ipad a lot on gigs via 5 pin midi output ) and price make it a great deal for a lot of folks--maybe others here. So now that I am gigging more and trying to increase the gigs, it just made sense. Once I learn the sound editing and setup methods I will know more about the "workstation" part of it. And the bonus is a fantastic support group via Facebook, with user generated resources, stage setups, tips, forum, etc.  
Good luck, of course, once you make your decision, I'm sure you'll be thrilled regardless of choice.

Well Dave. I looked more into the board and once again I appreciate your recommendations. 
 
It seems to have everything I will need or want in a keyboard. The Kronos would have been overkill for me.
It's light weight
Has a nice 88 keys weighted keybed
Has great bread and butter sounds particularly nice pianos
Has some arpeggio features
Has 5 pin midi and usb midi
Gets great reviews. In fact I couldn't find a bad review.
Records and plays back from a usb stick
Costs the same money as a good midi controller
 
So I bought one. And they threw in a free set of studio monitors with free shipping!
If you're in the states here's a link to the deal. You'll see the monitors in your cart at checkout.
 
http://www.samash.com/keyboards/digital-pianos/casio-privia-pro-px-5s-digital-piano-cpx5sxxxx
 
It'll be nice to have a weighted keybed again.
 
Thanks again!!
 
 

Wow! Free monitors? Dang, wish I had seen that, I was just happy to get free shipping next day from B&H!  This is so great, I've been following this thread and frankly I'm still a little bit fearful of bringing up the "Casio" name, as it was for so long (and deservedly) a name associated with "toy" keyboards and watches, etc. I'm very happy for you, I felt after re-reading all the posts that you might find this hit the sweet spot. I know you will love it. I, too could not find a bad review, and hopefully will be adding my own soon.
Enjoy! And don't forget about the support you can get from other users (more exp with it than me at this point):
 
Here's a link you might find useful:
http://sc3900.wix.com/px-5s   This is the user portal, I haven't been through much of it yet.
 
And if you use Facebook, there is a vibrant community of users here: Although it says the group is "closed" it is not, and I was accepted within minutes of requesting to join it. It feels like I have dozens of new friends who are sharing stuff about the keyboard (and it's newer cousin the 560), and the group is growing to almost 3000 members and climbing. 
 
Hope you find all this helpful, I know it's been a fun week or so since I adopted my new axe.
Dave

Tim, I should add your Celtic music page on Soundcloud is awesome! You have skills....