i'll admit i am partial to asus or asrock. what i really like about the extreme 6 is it is very flexible; not just a gaming board with a couple of pci x16 slots. if you need to get a legacy pci card or pci-e card there is room for it. and if you use the onboard graphics for anything, there is DP, HDMI, DVI and D-Sub connections.
Have you ever used the Extreme4 board? My budget is a little tighter than I expected it to be, and it seems like a crazy good value.