They are the high end of the industry.. as far as features, and overclocking are concerned. They are usually a little late to the party (products always come out after the others), but end up being one of the best.
I still waiting on the DFI 939 nf3 ultra-d AGP which has shown up on beta PCB, and is suppose to follow the their nf4 launch. They have remained steadfast that it will see the light of day, and i'm tempted to wait another month or so to see if they do indeed release it.
I just brought a 6800NU and have no urge to go to PCI-e yet.
Its getting real hard to not grab a MSI neo2 combo though...