I have a few minor gripes, or rather opportunities I think Cakewalk could gain some serious attention from in the Pro market, but overall, things have improved far beyond what I call the "X2 orphan".
Many of my gripes were those of stability and buggy issues. Many of those have been vastly improved upon since X3. And just like the company I work for, there comes a time when the priority or focus is placed on speed, reliability, and stability. If they continue this trend once in a while, Sonar should be a welcome change to those nay-sayers.
I'd still like to see Sonar compatible with Mac OS X, but building a PC is still cheaper, and Windows has been quite stable, lately. So, until Microsoft wets their own bed again, like they did with Vista, I'm here for a while longer.