I'm not running 7, but x64 Sonar 8 under Vista 64. Just recently got everything configured and my main issue has been certain VST plugs.
The issue seems to center around what's called "Teleport Server" which seems to be tied with Bitbridge. What happens is typically if the plug has some kind of authorization, the auth screen won't pop up like it's supposed to. Happened with
my Sampletank plugin and I found a work-around on the Cakewalk forums. Seems that newer .dll files for the plugs are working better *gradually*, but it's hit or miss. What seems to work is to install the plugs in a 32-bit application - I used Reaper for this purpose. The 32-bit Sonar seems to load the x64 Plugin Manager for some reason, so I simply installed Reaper, installed the VST plugs, authorized the plugs, then specified the plug folders in x64 Sonar...whammo. Worked like a charm.
Other than plug issues, x64 Sonar is running great for me. I'm overall happy with my Vista config over the XP Pro config I was using. Definitely snappier and more stable thus far. Driver for hardware are a KEY issue - make sure you have the latest 64-bit drivers (if available). If no 64, you're out of luck unless you're simply running Vista 32.
To the OP: if you do make it back to this thread, Vista 32 and the 32-bit Sonar should be a bit easier to cope with.