I own the Akai MPK261 and I'm very happy with my purchase. The controls were a little difficult to figure out in act cause it breaks them into 3 separate midi devices in Sonar but I can get most of the controls to work without a hitch.
I've never touched or owned the Akai Advance but the main selling point is just the touch screen and plugin integration software.
 
As far as getting better at Sonar, there's videos for sale in the Cakewalk shop they helped me a lot. For further education you can check out Groove3 and Lynda (Lynda teaches in pro tools but it translates to Sonar well)
 
Lynda has been a big help in getting my audio software skills up to par and I was happy with my subscription, you have to actually use it though and the information will take time to sink in. You'll probably go at it for 3 months and then not touch it for a while, from my experience.
 
Hope that answers your questions.

You may wish to sit back and think about what exactly you will be playing..
 
As you play piano, you may wish to think first about a piano keyboard... these can be controller keyboards as above, or something like a stage piano.. in my case it is a Yamaha S70xs (which is 76 key).. and used stage pianos are not much more than an 88 key controller with a quality weighted keybed. In my case, this sits to the side of my desk.
 
Now, once i eliminate the need for two handed piano playing from the needs of a controller on the desk, i can pretty much do the vast majority of play-in with a 49 or even a 37 key unit on the studio desk... and the space savings by losing one octave or more over a 61 note are significant.

Whilst any controller can be configured with some effort to work with Sonar, if you are looking for a controller that has plug and play deep integration with Sonar, the Roland A-Pro series is a great choice. Comes in all sizes, and for the money has quite a nice action.
I bought the smallest version to use when travelling and have been very happy with it.
 
http://www.roland.com/products/a-500pro/
 

TerraTkai
Hi TheMaartian,
 
I have Sonar LE atm but was planning the upgrade to professional I have already costed that in. Thanks for the link I have been checking out some of the sonar university videos (doh didn't see them).
 
I think the s61 needs K10 so I am factoring that in as part of the price too. I guess as a piano player I am really impressed with the demos I am hearing on the included instruments (I think there are 3 different piano ones). I'm probably never going to be churning out dubstep :-) so like you said I am not going to be doing much sound design (but who knows).
 
I think the s61 has really caught my eye, but I will try both and see how they feel first. I think I favour the text under the controls rather than on a separate screen. It will be parked in front of a huge computer screen anyway. I also like the light colour on the keys matching to the screen interfaces, seems very intuitive for it to work that way.
 
I see a lot of shops are still stocking the one that doesn't come with K10 Select (cutdown version), I might see if I can find someone with the latest package and then I can get the cross grade package update later and split the cost over a couple of months. I'll have a dig around...
 
This is tricky as I know so little about the subject, but you guys have really helped and given me other options, Thanks!
 
Terra
 
 

I couldn't read all the post. KOMPLETE 10 comes with a bundled offer with KOMPLETE S61. You will get better value.
Regards
S Ghose
 
EDIT: I have KOMPLETE 10 with S25. At that time I didn't realize it is so good specially the lights on keys will be that much helpful. So I bought 25 keys.

I have ben updating the thread in the hardware forum on my progress with my S61.
I have discovered how to set up the light guide to map zones in EastWest play and other instruments that do not do it automatically in Komplete Kontrol.

There is also miss information circulating that arpeggios and chords cannot be captured as MIDI in a DAW. This is not the case, you just have to route the MIDI out from the KK plugin (not the keyboard) to a MIDI track.

I bought an Akai Advance a few months ago and I love it. Haven't had and trouble with using SONAR Plat. I have Komplete Ultimate 9 and everything in it works great with the Akai. Setting up zones on the keyboard can be done but choosing the notes (A1 to C3 for example) or by dragging the mouse on the keyboard. Fast and easy. It has a nice plugin cache deal so the can browse presets and be playing on fro Chromophone and then click on a patch in FM8 and it is loaded instantly and even the tail from the previous preset fades out: not chopped off. I agonized over which keyboard to choose but have come to believe neither would be a mistake. The Advance was more than a hundred dollars cheaper for me. The large knobs and pads are really nice. There are 8 pads and 8 buttons that can be used for turningthings on or off or even assigned to notes so I can set up 8 more notes below the current keyboard location. You can set up as many as 8 diff instruments in the multi mode so you can layer instruments together. The pads are solo and the buttons between the knob row and pad row are mute. Lots of software with the Akai. Air Music Tech Transfusser 2, Velvet 2 EP, Loom( I really like tis one), Hybrid 3, with 2 expansion packs, Xpand 2 and Vacuum Pro. You also get Sonnivox 88 piano. Have fun making your decision, you won't make a mistake which ever one you get.

BassDaddy
Have fun making your decision, you won't make a mistake which ever one you get.

Very true.
 
I have collated my findings since getting my NI S61 here. http://forum.cakewalk.com/FindPost/3368341
 
Most of the reviews and tutorials concentrate almost entirly on integration with Komplete and I had to dig deep to answer some of my questions related to third party non NKS stuff so I put it all down in one place.