I, too, am happy with X2a, it's running very well here, no issues. The odd minor bug, but nothing that affects my workflow.
I loved X1d, but really enjoy the enhancements in X2.
I'm not sure everyone's issues can be put down to their PC's, though. Some, probably.
I think some of it may be down to workflow. If I don't use a particular part of Sonar that has bugs, then Sonar will appear bug free to me. Someone who uses it a lot will have a very different view.
I have seen many people complain of bugs that have turned out to be system related, user error, or misunderstandings about how a particular feature works.
I have also seen intelligent, savvy people who seem to have diabolical issues through no fault of their own. It must be gut wrenching to be in that position. I truly don't know why.
I do know that it is not always a system issue, though.