Review of GA-Z68X-UD3H-B3 and ASRock Z68 Extreme4 -> http://www.tomshardware.com/reviews/asrock-z68-extreme4-asus-p8z68-v-pro-gigabyte-z68x-ud3h-b3,2939-18.html
; in this case the ASRock Z68 Extreme4 was chosen the 'winner.'
Further, for high OC'ing I prefer the ASUS P8Z68-V Pro, or Gigabyte GA-Z68XP-UD5; 12+ Phases in my experience is the minimum of SB 'K' CPUs.
However, if you do not have a SB 'K' then none of this matters -- get the one that's the cheapest, offers what you need, and offers the best warranty. In addition, about the best service/warranty is EVGA.