Installed my Gigabyte G1 on Sunday into the older of my two PCs. I have an i7 4790k in the front room and a i5 2500k attached to the projector in by theater room (not overclocked as I stupidly bought a non-overclocking MB at the time).
Fully intend to bring the i7 into the other room, but need to run ethernet cable first (urgh).
Stuck it in the i5 just to see how it runs, and it's incredible even in there (although I'm coming from a 760, so it's quite the leap for me, maybe not for those on a 970 or 980), so I'm in no huge hurry to make the switch now - will probably wait until the next big AAA comes out to do that - although the i5 does have a tendency to lock up when left idle for a while, not quite sure what that's about.
Absolutely silent from my sitting position, I can see the fan stop light is on a good proportion of the time, even when playing the less intensive games, and I couldn't be happier with it.