I've bought Samp, Mixcraft and now Reaper I intend on using them all. After whats happen to cake I'll never put all my eggs in one basket again.

I have Mixcraft Pro 8 and Samplitude. Both are excellent IMHO but Samplitude is far more superior and I've settled in in on it being my main DAW. I like it even better than I liked Sonar. I didn't like Studio One at all but everyone has different needs.

Mixcraft = Yes
 
Samplitude = No
 
Studio One 3 = Yes

Studio ONE is ridiculously similar to Sonar minus a few things and adding a few things. If you want to master it just press F1 and read the manual from beginning to end.

If you don't need more esoteric audio and MIDI features, Mixcraft is a good choice.
 
If you want super advanced audio with pretty decent MIDI and serviceable Notation, Samplitude is a good choice.
 
If you want somewhat advanced audio with somewhat advanced MIDI, Studio One is a good choice.
Studio One's UI is very clean... and focuses heavy on drag/drop function.
 
If you're a hard-core MIDI user, Cubase 9.5 has an edge over all other PC DAW applications.
Note Expression, Notation, Logical Editor, etc
Very popular with composers...
 
Audio wise, Reaper is right up there with Samplitude.
The MIDI in Reaper is fairly advanced (Piano Roll, Notation, etc)... but not as extensive as Cubase 9.5.
My only "criticism" of Reaper is that it's configurable almost to a fault.
Reaper is probably the closest DAW app to being "Everything-To-Everyone".  
That level of configuration can be daunting for a new user (especially someone new to using a DAW).
Performance wise, Reaper is currently THE most efficient application.  A well configured machine can literally run a multi-core CPU up to 99% CPU load (at ASIO buffer sizes smaller than 64-samples)... and the audio will be completely glitch-free. 
 
Moving away from Sonar, it's hard for many folks to make that ultimate decision (which alternative will be the new number-one).  In large part because we're spoiled by good choices.
 

Mixcraft = No
 
Studio One 3 = Maybe/sort of
 
Samplitude = Absolutely!

I picked up both Mixcraft and the Samplitude package last month.  So far I like Mixcraft - as others have said it looks and feels a lot like SONAR 8.5.  I like the way (I think) the Matrix (Pad) section works.  I haven't come upon any shortcomings other than the lack of touch access.  But I haven't played with it much and tried to break it.  I love the look of Samplitude but haven't even installed it yet.  I have an idea I'll end up using it in the end, unless the Pad Performance capabilities of Mixcraft win me over.
 
I think Mixcraft is probably the quickest and easiest transfer of DAW knowledge from SONAR.  I think Samplitude would probably be the professional answer, if you are dealing with clients.  They might have heard of Samplitude (and probably not Mixcraft), and the screen isn't so MS-looking.  
 
Basically, I'm trying to finish up a couple of long projects in SONAR while I decide which of the above is a better long-term pick.  And I'm still learning Maschine and my Jam hardware I got last year.  I guess I picked a bad year to sleep.

I'm copying my reply from another thread:
 
After a week of Samplitude here's what I can tell you. It's a very DEEP program in terms of what you can tweak. I think it's about on par with Sonar and Studio One with regard to overall performance, but I did notice a few differences. In SPLAT when running Kontakt and other CPU heavy vsts like Arturia's analog stuff it was better to have the multi CPU options enabled in those plug-ins. Without that SPLAT would show uneven use of the system cores when the CPU monitor was set to "System". However the opposite was true in Samplitude. Disabling the multi core support in Kontakt and allowing the host to do handle the scheduling evened things out with the cores. Same was true for Studio One. This is on an i7 from about 5 years ago, 4 cores with 4 more virtual cores running the latest version of Windows 10 16 gigs of RAM. I've had some crashes, but it's worth noting that what causes crashes in SPLAT causes crashes in other DAWS. The biggest culprit is Drumagog especially when using it's plug-in hosting feature. It doesn't happen all the time, but it has taken down SPLAT, Studio One, Samplitude, and yes even Reaper. I also have an occasional crash when dragging in MIDI files related to rex files from NI Battery in from the media browser. This has also happened in all the DAWS mentioned above.
 
Overall, I like Samplitude because unlike Studio One it allows 3rd party audio editors like Adobe Audition and Soundforge. Reaper does as well and setting them up in those 2 programs is easier than in SPLAT. The Object editing feature is great and gives some nice mixing possibilities. I also think their audio quantize is way better and more efficient than Audio Snap. Never was a fan of how that was implemented in any version of Sonar. I've done some basic mixes, but at this point will hold off on any judgements on how the audio engine sounds. Samplitude doesn't yet allow track templates, except on the master bus, a bit of an annoyance. But they do have a built-in stereo imager on the master bus which gives mixes a nice width and depth without having to use a 3rd party vst.
 
As much as I like Samplitude thus far, I still think that if you check back with me in about 18 months, I'll be on Reaper. To me it's about one more solid update away which I'm told will be happening this year. If they add ARA integration and beef up the MIDI functions it will be my next DAW. It's the most CPU friendly of the pack by far, it's main setback being that it's very hard to just dive right in and start. I also do think that the folks at Reaper borrowed some ideas from  Samplitude with some of the functions, but most DAWS "borrow" from each other these days.

I'll add, if you have a use for Soundforge or Spectral Layer then the Magix Samplitude bundle is a great price.
Mixcraft I have demoed and like it and still debating on it. I went with Tracktion Waveform, Samplitude and Presonus SO1-3.5 for the upgrade offers.  I might hold off on Mixcraft to see what happens with Cakewalk now myself.
 
Tracktion was an easy buy for $50.00 special. Pattern Generator is really cool and now I have to dig in and learn Biotek synth. Samplitude was easy too because I had a need for the Spectral Layer program and had to use a friends to do what I needed several years ago. I couldn't justify the price separate sale.
Plus I always liked Samplitude but never could justify the crossgrade price in the past.
Presonus Studio one I think was an impulse buy. I figured I could use it to Master like Craig and several others here use it for. I just don't have the time to really analyze each one. As Jim Roseberry said earlier in this thread, Each has merit.  If you have some extra funds, I don't think it is a bad idea to pick one or two up at the sale prices to learn at your leisure.  I decided not to put my eggs in one basket anymore.
 

These replies have all been great!  Other thoughts are still welcome.