I prefer MSI mother boards, i have the MSI Z68A-GD80 G3 and i think it is absolutely great review can be found here http://www.pcgameware.co.uk/reviews/motherboards/msi-z68a-gd80-g3-review/
Hi I have actually seen the performance of a z77 it is a good performance board, just make sure that your memory is compatible with the board and you should be amazed of the quality
Assuming that you will only Crossfire in the future because both boards only support it, I would pay the extra money and get the MSI board instead of the Asrock mATX.