I ordered the aftermarket one. Not so sure I need it, the one that came with it looks pretty decent. But it wasn't so expensive, and probably is better.
One thing I'm wondering - it looks like this thing can do dual video cards, and dual HDD for blazzing speed. I didn't go with that. I dont' think I will - this thing can turn into a $3000 project if you don't stop somehwere, but it sure does sound fun!