I'm using onboard RAID-0 (striping) and it works very well. No frames ever dropped and no jumpiness. Very smooth.
It's an Abit TH7II board with a 1.6GhzP4 w/512K cache and 1GB RDRAM.
It's only a 400Mhz FSB board though. I got it this past April when 533 FSB boards were not around yet.
I don't know when, maybe in a few months, I am going to go to a 533 board with dual processors since I've heard my 6.5 Premiere will make good use of it, especially in the way of rendering. If the board I get has onboard RAID, I'll use it.