The gigabyte heatsink owns. It's a huge block of pure copper and cools great. Dual BIOS is a nifty feature also. I haven't tried abit myself.
The other board I have, ASUS P4C800-E Deluxe I have is ok and all but I am not too impressed for its cost ($180). Have not tried DFI either, it was out of my budget for this build.