I was one of the biggest critics of the length of time it took AE to get AV7 for Win out. But now that it's out, I find it great as ever, and still one of the top convolution 'verbs, if not THE best. And of course, they're obsessed with creating their own great samples.
The stability for me, on Win 7 x64 & Sonar X3 x64, has been great. No problems whatsoever. Can't speak to the new adjustment parameters, as I don't find I need them.
You should be able to demo, and check the stability out on your own system before you buy. Yes, the slow update schedule might be a concern, if you find instabilities on your system. I haven't.