I bought a G1 1080 which I'm very happy with - having an issue with one of the fans, though. Keep in mind this only seems to occur when it's on automatic and is stopping and starting with the "fan stop."
Basically the far right fan when spinning up is making quite a loud clicking or grinding sound, even in idle every now and again it will do it, the far left fan also spins (without noise) and the middle fan remains idle. It seems like it only makes the noise when running at a very low speed.
I've made a custom fan curve which seems to have remedied the problem, although would like to know whether this is common with cards with this "fan stop" feature? Still unsure whether I will need to RMA the card.