Nothing has blown up on me so far... Although, keep in mind, that I don't use Sonar, to the extent that many of you do. I use it mainly to drive Reason via rewire where there are tempo changes. Or, when I need to take advantage of a vsti. And, record a track.
But still do all of my audio work beyond that in Audition.
So, bottom line, I'm probably not a good test case for it's stability.