The popup menus now work. My render hasn't crashed yet, but hasn't had time to finish, either. I never had the "dialogs stuck behind" problem, but it seems now that may have been a symptom of an incompatible DivX plugin in the first place. Basically, the obvious problems I'd had before are gone. The fact that my render (on which I'd given up after numerous attempts) is a good sign but not yet conclusive. So at worst, it's substantially improved over SR1.