I have both a DVD-ROM drive and a Pioneer DVD-RW drive on my Acard 6280M and they both work fine. There's also a 40 GB and a 400 GB hard drive on the card.
The Pioneer is a DVR-111D. The DVD-ROM is a no-name I bought at Frys or somewhere years ago.
The Acard is in a Umax S900 motherboard (8500/9500 clone) and I'm running OS 7.6.1 through 9.1 depending on the situation. I use the DVD-RW drive with Toast Titanium 5.23 and I've burned DVDs on it, although Toast 8's built-in compression utility is much nicer so usually I do DVD burning on the OSX machine.
I'm currently using a PowerLogix 1 GHz G3 upgrade in the machine although I've used these drives with an earlier G3 upgrade. I watch DVDs on the machine using a Wired4DVD card.