I'm building a new gaming right and well I bought a motherboard already which is the ASRock Z77 Extreme 4. However I feel like switching to the ASUS Maximus V GENE. Do you think I should switch motherboard or is the one I have already better? I also plan on SLI 2 670s on this rig.
I wouldn't bother switching out, there's nothing wrong with the ASRock. I don't think there's anything the Asus can do that the ASRock can't, so I would just save my money. The black and gold on the ASRock looks sick by the way,
I'd stick with the ASRock board since you are planning to run SLI cards. Things will be a bit tight on the Asus board since it's mATX - those cards will be right on top of each other and will likely run a bit warmer than usual.