I did find Sonar X2 a very pleasing experience, love Breverb and the new improved FX chains. However, the stability aint that good, I had X2 crash 3 times today, and a couple of times yesterday.

I only had about 3-4 vst synths inserted, and 7 drumtacks of audio playing a short loop, a couple of FX. nothing more.

I could run a lot more on X1, on the same computer. I am looking forward to the next update!

CPU: i7-3770K 3.50 GHz
16 GB RAM, 
Win 7 64 bit

Audio interface: Motu Ultralite MK3 Hybrid

I had my first crash today but I was try to do things while the track was playing. I don't think that this daw likes that. Usually, I shut the track down when making an adjustment or inserting an effect. 

What did you do when your system crashed?

I have been experiencing problems with X2.  Crashes, strange Midi editing behavior, etc.  Never had this type of experience with X1 or prior releases.  So I checked my RME Fireface 800 buffer size.  Was set at 64 Samples.  I upped the setting to 128 Samples and was able to run the rest of last eventing (~3hrs) without any crashes or editing issues.  Actually had a chance to explore and enjoy the new features of X2 after the Buffer change.  I will try going back to 64 Samples and see if I can repeat the strange Midi editing behavior.  Clearly no logical correlation.

Nothing really.

Last time however, I did deleted an FX from a FX bin.

I ran at 128 samples, did go up to 256. However, think that I at least would be able to run at 256. With my desktop and a good FW card. Motu Ultralite MK3 Hybrid .

I'm having some crash issues related to FX insert and delete as well..I had thoughts it was my UAD2 solo but mainly crashes resulted from starting or deleting effect from the bin.
Oddly, my effects are showing as x64 in my X1 but only 32bit with X2 x64.
Rescans do not seem to be grabbing the 64bit folders and manually adding to VST scan provides no change.
My install was a non event, seamless and trouble free download and install...The Breverb is an outstanding copy of the Lexi 224 IMO, but this version in Cakewalk seems to have some related integration issues...lets hope I'm wrong....X2 is beautiful and really effective DAW that matter aside, and I'm sure I'll have a very simple fix to sort that out.
Because we run the 2802 for mixdown, I mainly mix in Cubase but use sub mixes from Sonar that I feel I cannot sonically capture in Cubase and although it may sound tedious, it actually works out really well. HUI protocol to bring Sonar into the 2802 would be smashing but me feels that aint gonna happen

Have Windows7 check you disk drive and memory. Make sure you have the latest version of the Motu's driver.