Well I've had every one crash or completely disappear at one point or another while working in them. Probably due to plugin issues. There is no "stable" DAW that I can tell.

For me Cubase has been reliable so far.

I've found Reaper to be more stable than SONAR in my experience so far.  As of late, I've found the audio engine dropping out quite regularly in SONAR, even under relatively light CPU load, whereas I've had no dropouts or crashes of any kind in Reaper.

I'm mostly testing Samplitude, DP9, & Mixcraft at the moment. Cubase has other issues so I won't be using it. I haven't tried Reaper lately.

soens
I'm mostly testing Samplitude, DP9, & Mixcraft at the moment. Cubase has other issues so I won't be using it. I haven't tried Reaper lately.

I would honestly give Reaper a try, I've been very impressed.  Basic recording functions are handled with ease and it seems to have a good number of advanced features.  MIDI support seems excellent.  It seems stable.  And it's extremely good value (I've not purchased a licence as yet, but I will be over the next couple of months.  I was going to, but when I saw the limited offer for Mixbus I had to get that first whilst it was a good price).
 
Another good thing about Reaper is most of the plugins you've used in SONAR will also be compatible.  There will be some you won't be able to use - for example, third party ones which are only licensed for use in SONAR (but then this would be the case with any other DAW as well).  Also, it natively supports the DX plugins, so if you use the Sonitus plugins, they just work.  A couple don't appear (notably the Sonitus Compressor) but again this is also an issue that will seemingly affect most other DAWs as well.
 
So, in short I recommend giving Reaper a try.  It is powerful and capable and may well save you a fair bit of money given the price it costs compared to other options on the market.

In general, frustrating, also I wished I would have created a restore point before installing any of them, got some weird things going on now, so weeding out all the crap that installed with demo's, and that isn't removed using uninstall, at least I did make an image backup prior to most.
While not 100% sure it was, I think CuBase (although not knocking software) was the most invasive in making unknown or requiring system changes to function, aside from all the authorizing to demo a limited version, it required making changes to personal Windows/GUI setting, i.e., Aero background themes required and no high contrast setting allowed or wont start, (which I use for my vision issues), and activating Windows sounds, also requiring USB dongle to demo full version, so not even sure of full functionality and costs $$ just to demo. This is important to see which and how existing VST's and VI's function within softwares. 
Also ProTools requires to buy ILOK3 $$ just to demo full version to use your own VST's and VI's, also I guess ProTools isn't offering any incentives to gain Cakewalk users. 
 
While I assume there may always be smaller players in the DAW market, these may be the most sustainable 2, and a new learning curve in all, its the sustainability thats a big part of my decision as well as sharing same file formats, I dont want to go through years of relearning a third time after this.   
 
Cheers
 
 

JohnEgan
In general, frustrating, also I wished I would have created a restore point before installing any of them, got some weird things going on now, so weeding out all the crap that installed with demo's, and that isn't removed using uninstall, at least I did make an image backup prior to most.
While not 100% sure it was, I think CuBase (although not knocking software) was the most invasive in making unknown or requiring system changes to function, aside from all the authorizing to demo a limited version, it required making changes to personal Windows/GUI setting, i.e., Aero background themes required and no high contrast setting allowed or wont start, (which I use for my vision issues), and activating Windows sounds, also requiring USB dongle to demo full version, so not even sure of full functionality and costs $$ just to demo. This is important to see which and how existing VST's and VI's function within softwares. 
Also ProTools requires to buy ILOK3 $$ just to demo full version to use your own VST's and VI's, also I guess ProTools isn't offering any incentives to gain Cakewalk users. 
 
While I assume there may always be smaller players in the DAW market, these may be the most sustainable 2, and a new learning curve in all, its the sustainability thats a big part of my decision as well as sharing same file formats, I dont want to go through years of relearning a third time after this.   
 
Cheers
 
 

I won't touch anything which requires ILOK.  Seeing as you have to pay for one of those ILOK things before you even get to needing to pay for the software which requires it.  I get the anti-piracy element, but to me that's just an incentive to find alternatives to buy.

Well, I'm certainly no safer using software that requires a USB $lothog!

I demoed Cubase, DP, Samplitude, Mixcraft, and Reaper.
Watched many hours of Video Tutorials for each.
Mixcraft is a no go for me, it failed the "loop back" test;
maybe I couldn't find the "use reported latency" setting?
I use midi for drums (EZD and Superior 3), keys and about 50% for bass (but I'm not a "power user").
Reaper is the only one that I quickly "warmed up" to.
I reinstalled Samplitude (all the "insane deal" raving and the fact that many I respect seem to lean that way)
and made sure I hadn't "missed" anything; nothing to see there for me.
I find midi editing much easier and intuitive in Reaper; (but maybe I am ADHD; nah, I passed that test).
The one thing in Reaper I found "lacking" is "bouncing" tracks;
the whole "render" thing is taking a little getting used to, for me.
Copy/Paste is a little "klugey" as well, compared to what I'm used to.
I will say this, I'm "anchored" to SPlat and feel sure that my systems are "safe" even if/when the servers die.
I've yet to verify it, but if aux tracks are the issue with going back to X3;
I'll slowly make sure all projects have an "aux free" back up.
I'm not saying you'll have to pry my dead cold fingers from SONAR, but until it "fails" me;
SONAR will remain my go-to DAW.
 
T
 

Ableton Live has been far more stable for me the last few years than Sonar...