BobF
On a whim I installed the S1/3 Pro demo a few weeks ago.  Once I finally got everything downloaded (I have a slow-ass internet connection), I was immediately impressed.  I was so impressed that I purchased a crossgrade license as soon as a sale went on.
 
I have now spent a bit of time with it and honestly, there are things I like and things I don't like.  Just like every other DAW I've tried.
 
I'm currently working on a flow that starts with S1 ( arrange/scratchpad ) and later migrates to SONAR for tracking/mixing.  I expect to end up back in S1 for mastering.  I'm hoping that the pending Ripple Edit in SONAR will make the arrange/scratchpad features of S1 less appealing.
 
The simplest explanation I can come up with is that S1 is quicker to get started, but SONAR has the advantage when it comes to details.  Keep in mind that I have thousands of hours with SONAR and a few hours with S1.
 
But ... the jury is still out.  Ripple edit and a few other tweaks could easily make S1 an afterthought.  Well, there is the integration with Notion 6 that I haven't even started to explore yet.

 
Hi Bob.
This is intriguing. Can I ask how you transfer your projects between Splat and S1? I would love to give this a try.

Anderton
I think the only conclusion that could be possibly be drawn is "Different DAWs are different, and often do things differently."

Another conclusion is that when other companies find a good solution, it is a good idea to take notice of that. I don't think anybody here is bashing either company and I appreciate the range of views and observations.
 
I'll add another usability difference because SONAR bit me in the butt for the the 100th time tonight (yeah, I'm not a very quick learner.)  When you want to export a mixdown in SONAR, you have to be very careful to select every track, and also set the ruler. If you let the ruler set to the clip lengths, then you chop off any reverb at the end. And if you are not careful when setting the ruler, you will deselect tracks, causing that material to be left out of the mixdown. I can't tell you how frustrating I find this process because when I want to do a mixdown, it should be obvious that I want every non-muted track and I want ALL the material including the tails.  SONAR is really tedious about this.
 
I didn't pay attention to StudioOne to see how it worked differently.  And that's the point. I didn't have to pay attention. It just worked.

You can add time to the end of a song bounce for reverb and set the length.

AT
You can add time to the end of a song bounce for reverb and set the length.

I'm sure there are many work-arounds.  The point is that it shouldn't be necessary. I realize that many of the people here have decades of experience with SONAR and its various quirks. If a company wants to appeal to a larger market share, it is a good idea to work on making the experience as non-tedious as possible.  Cakewalk has made some efforts in that regard, but ultimately I think that is the ultimate difference between the two products compared here. StudioOne is less capable and less tedious.  It need not be a trade-off.
 
And I rarely bounce anything.  It seems to me bouncing is a tradition here, but it just isn't something I find much need to do. Why bounce when what you want to do is export the mixdown?  Isn't that what Export is for?

I have sonar platinum and have been with cakewalk since buying producer version 8.5 back in 2009 I think... I also have studio one - 2 professional. I have yet to track a single song in it. Though I keep saying I am going to try it. I use it primarily for mastering. Simply because it can export with more meta data baked into an mp3 including a bands' logo... AND THEY LOVE THAT! So when a band puts their new mp3 on reverbnation, or itunes, even just their phone it is already there and it looks more professional. I also love the song/project (album) workflow of s1. It is brilliant that if you update the mix on the song, that automatically updates the associated mixdown file in the mastering project screen. So smart and soo useful! Though I have never taken advantage of it because I love to track and mix in sonar...
If cake implemented better mp3 export options and a linked project file that worked like s1 for mastering songs on an album together I S1 would never see another dime of my money. I Agree with a couple others here about sonars mixdown options being a little insane and counter intuitive. If you have a clip highlighted (because it's the last thing you clicked on and edited in Track view) it sucks! Have you guys ever done this? You make the mistake above then you click export audio... export a wav., burn a cd, wait for it to finish, shut your system down, turn off the monitors and your gear, satisfied you have a solid mix, go out to the car to do some errands, pop that cd in and listen to a 4 minute long mixdown of JUST YOUR SNARE TRACK!!? aaaaaaaaahhhhh. WTF??!! I hate that part of sonar with all that I am, because it has burned me so many times. Send a client home with an mp3 of just a ride cymbal track and they go to show their wife their new song as soon as they get in their front door... you get the dude WTF is this sh@t!?#*!! Phone call every time!

I have just picked up Studio One 3 Professional (Windows) at a great price and have only had it installed for about a week. I am a long time Sonar user (now on Sonar Platinum with LT updates) so it would be unfair of me to compare both at this stage. It is interesting to hear some of your viewpoints and findings though. I liked the look of the Arranger and Scratchpad which are the main things that attracted me.
 
So far I have found it pretty intuitive apart from one strange installation anomaly for the extra content...you register your code on their website and it then tells you to download the content (30 files, around 33Gb). After manually doing this (I use FreeDownloadManager) and installing the program you then tell it where you downloaded the content to and where you want it installing. It then goes ahead and DOES NOTHING! It uses the content just fine but in the location you manually downloaded it to and doesn't move it anywhere. Of course after doing it this way I discovered that if you download the content from within the program instead it will behave as expected. For most of the content this doesn't matter too much - just move the .soundset files where you want them and point S1 at that location. However, for the demo files these don't show up in the main opening screen unless you download them through the program. So I re-downloaded the demo files (265Mb or so) from within the program so that they show up on the opening screen (some of the demo songs are pretty complex and well worth studying). 
 
Groove3 has quite a few videos on S1 and I am working my way through their "Create Your First Song" in Studio One --> https://www.groove3.com/presonus-training-video-tutorials/First-Song-with-Studio-One-3 actually re-creating the song that Eli Krantzberg makes in the video. I find this an excellent way to get up to speed quickly with the main features.
 
It's been rock solid so far and I have had no crashes. I find it much snappier to load and use than Sonar on Windows 7 (Sonar takes ages to startup and scanning VSTs is painfully slow), but on Windows 10 both are similar.
 
In Sonar I have also suffered the "empty" mixdown syndrome reported by others but you do get used to it. 
The main thing that frustrates me with Sonar (since I started originally on X1) is how the "selection" of items works. Things seem to be selected that I don't remember selecting or at least not intentionally. You have to be very mindful and careful of where and when you click! I regularly found myself carrying out operations on parts of a song that I had no intention of altering. I now find myself, before I make any major change, doing a "Edit - Select none" (Num 5) to avoid any catastrophes.
 
ZT
EDIT: Also I tried the free S1 remote iPad app which works flawlessly but then again TouchDAW (paid) on my Android tablet also works fine with Sonar. 
EDIT 2: The other thing that's pulling me to S1 is the Notion 6 integration and upgrade price as I will be working more with notation this year.

I have Studio One 3 that I got when I purchased a Presonus hardware item.  I don't use it but I recently did for a test.  I'm having problems with Sonar when mixing down mono tracks to a stereo tracks, there is a slight (0.75db - it was more but uninstalling Sonar and reinstalling it got it down to the 0.75db) difference in the two tracks.  For testing I exported the mono tracks from Sonar and imported them into Studio One 3.  I did a mixdown in Studio One 3 and the mixed down stereo tracks have identical levels.  Can't say anything else about Studio One 3 as I don't use it, but it does accurately mixdown, where my Sonar does not.

the studio one gui fits on my laptop screen (1600x900)

ChuckC
You make the mistake above then you click export audio... export a wav., burn a cd, wait for it to finish, shut your system down, turn off the monitors and your gear, satisfied you have a solid mix, go out to the car to do some errands, pop that cd in and listen to a 4 minute long mixdown of JUST YOUR SNARE TRACK!!? aaaaaaaaahhhhh. WTF??!!

Replace "CD" with "SoundCloud" and that is exactly what I did last night. And it went one step further. I even embedded that SoundCloud into a website before I discovered my file had only the narration and not the three sound clips that were the main point of that file. It was deceptive because the file begins with narration, so when I played the first bit of it, I assumed everything was there. At least I didn't email the client saying the job was done.
 
And the catch-22 of that selection thing has another aspect.  If you select the clips, that resets the ruler, which then clips off the reverb tail.  You can't just do a Ctrl-A to select all of the clips. But if you go set the ruler, you are prone to deselecting tracks if you don't do it just right. I suppose this all makes sense to some designer somewhere, but every time I go through this process, I feel like Cakewalk is trying to drive me insane.
 
With StudioOne, you simply say Export Mixdown and it is done.  In this case, you can set start and end markers for the song, which I did, and that assured the tails got included. Those markers never move on their own so unless you add length to your song, you set those once and never have to worry about the software biting you in the butt.

I should add that I find SONAR's window management mostly easier to use than StudioOne's. I think it is more intuitive to get the windows set up and spaced the way you like with the contents (e.g. visible tracks) as you want to see them.  Unfortunately, much of that is lost when you shut down SONAR and you have to repeat the process on the next start-up. But it goes quickly.
 
On edit: I note the post above about Studio One fitting on a laptop screen. I use two 27" monitors, plus a third monitor to stash VST windows and other paraphernalia.  It does seem that the StudioOne screen is naturally more compact. For me that is not really an advantage, but I can see how that could make a difference on a laptop. I don't know that there is one "right" answer here. The only time I use a notebook is when I am tracking live performances and I would never, ever use a DAW for that.  I use Waves TracksLive which is purpose-built just for live tracking and eliminates all the stuff you don't need when tracking a live show. But that is just me. Others have different requirements.