Nate,
A good proportion of my team uses the Matrix. They are good markers. They have an unbelievable rate of fire, and are dead easy to fire fast. One of the drawbacks on the standard Matrix is that it's a gasguzzler. This can however by countered by installing one of those funky bolt kits. Also, the Matrix is gentle on paint, and if you install a trinity regulator, you'll never chop a ball again.
If you are going to get a Matrix, I'd recommend that you make sure you get a 4500psi air system with it, otherwise you'll be out of air real quick. Although it is possible to run the Matrix on Co2, but that stuff is harsh on your o-rings. And since the Matrix is reliant on a good number of o-rings, I'd advice against Co2.