I've been using Parallels on my Macbook Pro since I purchased it, because I still need to do a fair bit of stuff in a Windows environment. I occasionally do some work in Visual Basic, as well as Access - both of which aren't available under OS X. I'd been running the 3170 build for some time, and whilst it was totally stable, there was an irritating bug in it which would cause the fans to run at full whack (around 6kRPM according to iStat Pro) after a few minutes use. The processor and memory usage would rise significantly. Until now, I'd just put up with it.

Obviously, this was an older version. Today I upgraded to Build 5592, available here which certainly seems to have fixed the problem. The look and feel of the container has changed as well, and it just feels, well, nicer. Well worth the upgrade.