Well, I've been using it every day for a week, as per the suggestion of a few other forum members - and I watched Seth's video. Still not all that excited.
Stuff I like:
PRV editing is much more intuitive (a very subjective word, I realize). FX Chains in the PC is awesome! I find myself using it way more than I did in X1, knowing that I can add in VST plugins before, after or in the middle of anything else.
Stuff I don't like:
I'm sure I'm in the minority here (perhaps I'm the only one), but I really dislike the Snap to Grid updates. Not that I thought it was perfect before, but I frequently turn on and off landmarks such as Clips and Midi Notes. Having to pull up a separate screen to do this is a pain. Those used to be accessible from the Control Bar module itself. Additionally, I like Smart Grid in theory, but I wish I had the ability to define at what zoom level individual resolutions were triggered. For most of the detailed editing I do, I would go to 1 Sample way sooner.
Many of the changes to the Smart Tool and Track View editing do not seem to be improvements. They don't necessarily seem worse to me, it's just as though they've moved stuff around; e.g., grabbing a clip to move it is now done on the top of the clip rather than the bottom. 6 of one...?
Things that don't impact me:
I've got too many amp simulators already and the stuff I would use R-Mix for I can already do with RX2.
Ultimately, I don't regret upgrading and am still a very happy Sonar user. I'm sure X2 will evolve - X1 sure did!