It's still too fresh of a product really to make a clear winner out of that. I thought I was the only one piecing together a 775 system, so that makes me feel good someone else is interested! I've been researching the hell out of this sort of topic...
The Asus and Abit both have their seperate ideas on how to get a good overclock. Abit is making fat paths with those strips of metal around the CPU (it has worked wonderfully in the past) and using some great components to keep the smoke in. Asus has also implimented some good ideas with items like the Stackcool which is basicly another layer below the CPU.
I've recently recieved the Asus P5AD2 Premium after some tough thought. I really wanted the Abit as their name just oozes OC! But, I'm a probaganda whore and loved that Asus is trying to stay a step ahead by advertising the DDR2-600 Support. And my favorite memory maker (OCZ) seems to cater to Asus in the recent past by saying the DDR4600 was only certified with the 800-E deluxe. Add to that the HyperPath2, StackCool, AI NOS, and the C.P.R. feature (that lessen's the hassle in bad OC's) I figure the features are worth it to me and once again crossed over to Asus (it's been a while!).
And though it costs more and at the moment is very hard to find, the dual gigabit Lan(!) and triple RAID...I just felt it was the right decision.
The Abit, however, is going to be abundant (I've already seen it at the local Fry's). It's also a fine board at a lower cost than this thing. I'm a bit curious as too how it'll run because I'm still waiting on OCZ's DDR2 and a PCIE card to purchase, but the board itself looks very complex compared to the Abit AA8. The thing is just packed with traces and components! It must be like a 6-layer from the looks.
I matched it with a P4 550 (non D0) due to the way it seems to handle power. Again, I can't confirm, but from the reports it looks like the power consumption is treated differently and doesn't get up there until it's really utilized. Take a look here for a glimpse of what I'm trying to get at:
http://www6.tomshardware.com/motherboar ... 75-49.html
It's way down there on the bar-graph with the Athlons and P4B's. I can't wait to test this myself!
That entire article is worth looking into to aid in your decision. Any of them will be good to run, I just felt the Asus will aid further when I'll have to change again in in 925XE upgrade (Q3?).