I believe the only difference is in the number and type of PCI slots and overclocking ability. For me, as long as I have a PCIe 3.0 for adding a discrete gfx card if want to game, I'm good. Overclocking is a waste of time IMO.
thats about what I read about the difference. I have all so read about the overclocking not being needed. Reason I ask i was looking at the h77 model that was recommended for a media server build, which ran about 79. I figured for 30 more if I went to the z77 and the got the free 60gb hard drive. I guess really I am only saving about 20-30 on the hard drive.