I do agree that it's great for racing games. SOME fps games work ok, mainly source ones, but most RTS games either don't work, or give extremely low FPS like Dawn of War II
I do think in a few years it will be sorted and video cards will have the juice to play games at their best in max details.
I used to play Dragon Age a lot using Eyefinity, but from one day to the next i was never sure if it was going to work properly (and thats an official Eyefinity supported game!)