All of them are good buys, unless you get unlucky like quite a few people have been (including me, with my asus 970), and get fan issues and/or annoying buzzing noises (coil whine). Most of the complaints have been with the EVGA and MSI cards I believe.
In terms of performance in games, there's not too much difference. Gigabyte has two very long cards, one of them has a backplate (the G1). MSI has 2 cards as well, the "Gaming" version has semi-passive cooling which means the fans won't spin when you're not gaming or anything intensive, to keep it as quiet as possible. EVGA has a ton of cards, usually the FTW is the fastest, and the SC second fastest. There's also two different cooler options, preferably get the ACX 2.0 version. Then...