I've got Gigabyte, Sapphire, Powercolor and Asus.
The Asus cards are nice, but not very fast and they're expensive. Sapphire are OK, but the fans wear out very quickly. Powercolor, well one of them popped it's VRM (5870), and the other overheats all the time (6970). The Gigabytes (7950 with the 3 fans) are the most consistent - they mine well, they run cool, and are quite quiet.
I run my main mining rig in the living room, behind the sofa. It's got 3 Gigabyte 7950 in a Define XL R2. It's quiet enough to leave on while watching TV, and it does a great job of warming the downstairs of the house. I used to have it upstairs, but it ended up that upstairs was about 28C and downstairs was 18C. Now the house is an even 24C.