I've had excellent success with many Sapphire graphics cards over the years (going back to the clearance-priced Radeon 9500Pro that after a BIOS flash became a Radeon 9700). I'm 0 for 2 with PowerColor.
There's not a huge amount of differentiation among the Radeon HD7770 cards. They all do quite well for their low price.
I will also agree with DPete27's recommendation against a Radeon HD7850 1GB when the 2GB versions are almost as cheap and won't have a seizure when you load Skyrim's HD texture pack.
i7-4770K, H70, Gryphon Z87, 16 GiB, R9-290, SSD, 2 HD, Blu-ray, SB ZX, TJ08-E, SS-660XP², 3007WFP+2001FP, RK-9000BR, MX518