It's the same price...
which one should I get?
The Gene-Z is sexier
lol, but the P8Z68-V has more PCI Express slots (though I will only use two max [if I get another gpu]).
U will not see any differences between them really.
But if u like it, get it. U will not go with bad or weak mobo : )
It has better audio chip.
SupremeFX X-Fi 2 x 8 Channels
Smaller mobo will get hotter, but u have good case, so I think you are just fine there.