The Sapphire fans are smooth as silk, anything 69% and under is tolerable. Lower speeds are nearly inaudible depending on your setup. The Gigabyte cards are also fantastic. MSI is good too.
Sapphire is voltage unlocked, while Gigabyte is locked, not sure about MSI. Though with the 7950s I don't think that matters as people around here are getting fantastic hashrates as well with the Gigabyte and MSI cards as long as you're using them for --scrypt.
Although if you want to power save you'll want to flash different bios on the locked cards. The Sapphire undervolts very well while even overclocking a bit. I'm speaking for the 7970s though, but I imagine the 7950s might be similar.
You might want to check out this thread as well;
https://forum.litecoin.net/index.php/topic,2641.0.html