First off, a few years ago I swore I'd never use Parallels ever again. I has nothing but troubles with v5. So I started using VMware. It was much more stable than P5 but, for some strange reason, it does not play nice with a trackball I have. So I crossed my fingers and tried P7. What a difference! It runs fast and works with my Kensington. Because I owed VMware, it was just $29! http://www.parallels.com/products/desktop/vmwareoffer/form/ Sooo, I have Win7 and XP installed. Why not, eh? Which one do you prefer? I don't play games. Most just do office stuff and run some programs that only work on a PC. I have a top of the line 27" iMac with 16gb memory. I gave Win7 two CPUs and 2gb ram, XP, half of that.