Only problem I have with graphic cards with fans is that in CF or SLI they can get really hot if you don't have good airflow in between the cards.
My 7950 was one of those ref boost cards on a 7970 PCB, luckily picked up my card and block for only $250 and still got the game codes
. Coil whine really isn't bad, I get whine on the exit screen for Heaven but never during gameplay. My old GTX470 would whine while folding as well, both nvidia and amd cards have whining problems.
7950 is no joke at higher clock speeds though, even on the stock cooler getting 1100mhz was simple and fan noise really want bad.
My only problem with the 7950 boost is that because of it being a boost card I needed to mod my bios so I could get 50%+ in power tune, otherwise my core clocks would throttle down while overclocking at high voltages. But my card also has a low asic score of 58.6 what makes the boost problem worst, if you have a higher asic score it probably won't affect you as much.