Mixed bag really... in various systems I've got an Aopen 32X CD-ROM that works only sometimes, an Aopen GForce2 Ti that works ok but several of the features it was supposed to have don't work. BIOS updating and overclocking via the BIOS (an Aopen exclusive technology) is broken and for some odd reason it doesn't support nView Clone Mode or Digital Vibrance (which it didn't mention on the box when I bought it). The TV out is goofy... you can't display the desktop on the monitor and TV at the same time, it's one or the other. Tried to get tech support for the GF2 Ti with no success.
On the other hand, the company that owns the building I live in had me install and configure WinXP for two Aopen nForce2 board systems and they are running fine so far except that the Northbridge fan on one of the boards died so needs to be replaced. Haven't tried overclocking these two systems yet though... cheap ram
Based on my experience with Aopen products I wouldn't recommend them but you could do worse.