A couple of weeks ago I installed a copy of Parallels Desktop for mac. The main driver at the time was that it would allow me to play typing of the dead!!I have been using it since the first week in August. I think parallels is a great product, but I just recently switched back to VMWare Fusion as it was a clear winner in performance (my perceived performance). Parallels also seems to be somewhat of a resource hog. When I first had it installed I installed Windows 7 on a vm allocated 2GB of memory (my MBP has 4GB). I was also running an Ubuntu VM on vmware fusion that serves as my git repository. After about 30 minutes of running the Windows 7VM the Ubuntu VM would error saying that it could not allocate enough memory to continue operation (keep in mind that this Ubuntu VM was only allocated 256MB of RAM).
After switching back to VMWare fusion I can run both vm's quite happily and I am keeping the Windows 7 parallels vm kicking around so I can fire up typing of the dead every once in a while.
Develop With Passion!!