My P67-UD4 does a better job of OCing than my ASRock one. Might just be my particular board, but who knows. I've had 5.5ghz on a 2600k in this puppy
I also just find some of the 'features' of the ASRock one to be annoying... like this boot OC check thing and whatnot. I have the say, the ASRock Fatality board is nice, but rather than the Extreme 4 I'd definitely suggest going with a Gigabyte or Asus board. If you want to save some more money, the MSI boards are real cheap on NCIX, and even the somewhat base model P67A-G43 supports SLI.