I don't think motherboard choice will have a big impact on gaming performance. Any Z77 chipset motherboard will give you good overclocking ability, although complete unknown brands should still be avoided. I think Gigabyte is an ok brand, but the ASRock Z77 Extreme4 seems to be a more popular choice for a gaming motherboard. Does the Gigabyte have some features you need that the ASRock board doesn't?
I actually think the ASRock one looks better. Plus it's cheaper. It has all of the ports that I need too!
Does it get a lot of DOAs and do they replace DOA ones?
ASRock is a gold brand but I think gigabyte is better. ASRock extreme 4 is really good for he price but if you can afford more than that I'd say go for gigabyte g1.sniper 3 $260 or gigabyte z77 up7 $400