Yes this forum really shines (by a vast majority of time) on the helpfulness of peer to peer networking.
 
On the 'X' series: They have all been stable for me. I did have some issues but they were largely my misunderstanding. Once I solved it I was always good to go. Fortunately the problems were fairly easy to solve and when I couldn't solve them there was always this forum.
 
On the sends AFAIK it is still stuck on 2. The issues with UAD that I recall were solved some months back although to be fair I have stopped using UAD. Can't comment on MCU. I think the change in automation editing going from pre 'X' series to 'X' are largely (though not entirely) one of having to relearn or understand how it is supposed to work. I haven't been having problems of late although in X1 I was going batty for a week or so.
 
I'm in a position where I use other DAWs (Cubase for its video, Live for sketching out ideas) but I can say that Sonar is 'still the one' for me.
 
I would recommend waiting for Cakewalk providing a demo version of X3 and then taking it for spin. Personally I think you'll like it.
 
Regards,