Well to enlighten you
Z75 mobos are identical to Z77 boards but lack a few key features.
Lack of SLI/Crossfire (1x PCI 3.0 x16 slot 1x 2.0 slot x16 (runs as 4x)
Lack of intel SSD caching
those are the 2 major ones i know of , not sure if its lacking other features. but so far i can say its an awesome board