For an extra $15 your getting the newer version processor, which uses less power, runs .1ghz faster than the older one and will actually benefit more from the technologies on the z77 motherboard. IVY runs cooler and faster than sandy, just doesnt OC as well.
the differences between the two boards falls into what your getting, whilst ASRock have come a long way in the past few years, gigabyte's technology when it comes to load-line calibration, and 'auto-tuning' along with their back end support and their' years of making their boards the 'best', they have a better pedigree which is shown in the 3d bios and onboard features.
if you want to save $10 and go the ASRock by all means, its also a good board, but the push-button OC on the gigabyte, coupled with its power delivery is what grabbed me as the better buy, without experience in overclocking the gigabyte might be the better option...
AMD drivers is less a point of contention as it used to be, but both are about as stable as each other. I still believe the image quality and the graphics power behind the amd cards is pretty decent, whilst nvidia seems to be more geared up. at that price point tho, your getting more features and card stability Vs the 560 Ti's all round good-ness.
Nolite te bastardes carborundorum