My biggest disappointment with Parallels is their support. In this respect, I think they're about even. Granted, all these things are relatively unimportant compared to how well Windows programs run within the virtual environment.

I also like the way you can choose how it transitions (cube, flip, etc.). It might seem silly, but I prefer the way the screen transitions to and from Full Screen mode in Parallels (the rotating cube) as opposed to the 'dissolve' mode in Fusion. I think Parallels is a little more customizable. I think it needs some refinement so that the menu tree can be rearanged so that folders can be listed before or after individual programs. One thing *really* like is the ability to hide the Windows task bar and launch applications from the OS X menu bar. My initial impression of Fusion is that I like the interface it looks like a Cocoa application ('Mac look and feel'). I'll do that when I make a final decision.

I'm using the same copy of Windows XP I just haven't activated it yet. I'm not using a Boot Camp partition (for either Parallels or Fusion).

After hanging around these forums for a while and reading the 'which one is better?' threads, I started seeing LOTS of posts endorsing Fusion. Up until then, I didn't even know you could run Windows on a Mac. I purchased Parallels before I bought my iMac because I'd demo'ed it at an Apple store and was very impressed with it.

Parallels versus fusion gaming