Yeah I was considering that ASUS as well, but I read somewhere that it's OC'ing ability isn't on par with the Giga/Asrock board? Any truth to that?
I am not into OC'ing but I know that IB CPUs have an upper thermal ceiling while SB's have a better thermal headroom. That means that OC'ing 3570K is more of a processor architecture issue. from what I have learned here and OCN is that with the ASUS board you will get ~ 4.5 GHz stable OC. I am no OC expert and I'd recommend you ask this question on the OC section as well.