I checked the Krex page. The barebones system uses the Amptron board with an ALI GFX chipset. Said to be same as ALI TNT2. Might be TNT2 graphics chip.
Sounds like OK deal, if everything works. If you went and bought all those components individually, it would run you about the same -- assuming you scrounged for heavily rebated mice, keyboards, cdroms, lan nic, etc. However, for a 100 or 200 more, you can get a complete system with CPU, mem, and hd. I think vendor reliability is really the key here.
... so my final recommendation is, too close to call (sound familiar)