I ended up choosing parallels because it had, in a couple different reviews online, performed better in benchmark results. It was the only 'objective' advantage I could find for either.
Next time Apple updates OSX though, you'll be paying a pretty penny for the required Parallels update!
It does work well though. I'm able to play games, certainly run MS Office with ease. VMWare and Parallels both have modes that allow applications to work as if they were native mac apps (click the app on the dock, app opens up, no windows desktop or start menu, etc.). The UI of the app itself is windows but it works otherwise; as if it was a native mac app.
Here's what I mean;
Ultimately it is a 'coke vs pepsi' debate, and you'll probably be happy with either one.
Ford vs. Chevy, Coke vs. Pepsi. There are minor differences in the products but your previous experience with VMware might be a benefit in using it. I use Parallels and it does a good job but I'm using Windows less and less these days. I think I've run Windows about 4 times in 2013.
Unfortunately I need MS Office compatibility. Rather than shelling out for Office for Mac, I just used my existing licenses for both Office and Windows 7 I had available and installed Parallels. Then I get perfect compatibility (I've heard some issues with compatibility in powerpoint between Office:Mac and 'regular' office, and PPT is where I need compatibility).
If not for MS Office though, I would never use Windows. For anything that doesn't need to go on a Windows PC, I use iWork. Pages, numbers, etc; and far prefer them.