I've used sharkoons and do like them, but just for the feel of them there's something nice quality about nexus ones. The movement is really fluid. And honestly all the ones I've used have been noiseless as far as I could tell.
But the sharkoons are good too, just annoying because I can't work out how to control the speed from the AUX headers on an Abit NF-M2 motherboard. That's not fan specific though, that's the board