Thanks lotech. I recently tried out a Mac Pro so I'll add a couple things.
If you're a VJ running 3-5 layers of 1080p content and typically have 1 or 2 1080p outputs (plus monitor), pretty much all configs of the new Mac Pro will be fine for you. As far as graphics power it's definitely better than the latest Retina MacBook Pro. Once applications and OS X get more optimized for Crossfire the performance should be even faster.
I committed to Thunderbolt a while ago so I didn't mind all the dongles hanging out the back, but it could be a problem for some. In bass-heavy environments you should tape all the adapters and strain-relief cables.
Hauling the Mac Pro around was a bit of a struggle mostly because I had to carry a monitor with it. The tower was in a Pelican 1560 along with adapters, keyboard, and mouse. The 20" monitor was in my suitcase. I'm sure there are better ways to pack all of that especially if you use custom foam. I was paranoid about airlines tossing the case around so I overpacked the padding.
In my particular case I'm not in a rush to get the Mac Pro. I live on the road and in airports so a desktop solution is only worthwhile for the most demanding setups. In a studio environment this would be really nice though.
