I paid for VMware without trying the other two. I would said it was a bad choice.
VMware Fusion 3 is VERY, VERY, VERY, VERY bad for the graphic. I tried Parallel, so much better!
I tried playing Warcraft 3, the following problems encountered on VMware Fusion 3:
1. In full screen mode, you cant change the resolution in game. I don't know what's the problem. Parallel has no such problem.
2. In non-full screen mode, the colour sucks. Looks like 8-bit colour, seeing all the artefacts clearly. Parallel's display super smooth, true 32-bit.
3. When you move the mouse out of the VMware window, it goes out of VMware environment directly. Parallel trapped it properly. Not saying Parallel doesn't allow you to move the mouse in-and-out directly. But in gaming, somehow it is smart enough to trap the cursor.
When not playing game, and was in VMware Fusion's unity mode, you can see the cursor flickering, and moving the cursor was experiencing delay. Sometime when your Microsoft Window's application window is enlarged for sometime, VMware warned you that it experienced bad performance! From time to time, pop-up window couldn't be seen properly, there was an overlay over the window. You have to retry to get the window pop-up.
If you want to use Mac and Window application concurrently, and if you are dealing with some form of graphics, don't choose VMware Fusion 3. I paid for it, I regretted my choice. Believe me. And I have no way to get support from VMware. sucks.