To be completely honest, the next system I build is actually going to be the Z77X-UP7 and an i5-3570k.
That board overclocks like an absolute dream (current world record holder) and I have gotten to the point where unless I am going to go completely overkill for bragging rights (SR-X with a couple E5's) I would rather get better performance for cheaper, and drop extra money into another GPU.
My Choice is the Z77 with an i5 or an i7 (if using it for gaming and day to day use go with the i5. If using it for a lot of photoshop / or video editing [not talking about a couple times a month here, talking hours daily] than go with the i7. Hyperthreading is not important in day to day use at all)
The RIVE and Extreme 11 have better powerphases, and OC related tools (memory reset, voltage monitoring ports, OC buttons on the MB itself) and better heatsinks. They also come with some tools and features (Asus OC Key, attaches to your GPU and displays system info on your screen) or the ability to use another computer to directly control the BIOS.