Within the past month or two I've bought three different XFX cards from the HD7000 family; the HD7750, Double-D HD7770, and Double-D HD7870. None have given me any trouble. All are quiet, and easily as fast as I was expecting.
Of those you list though, I'd also choose MSI. When I was looking at HD7770s, I found a review somewhere (sorry, don't remember where) of one of the Sapphire cards that had an iron-core choke (rather than the more efficient ferrite-core) on one of its VRM circuits. That's a piddling details, but if it is the only thing to go on, I'd take the MSi. Gigabyte and Powercolor are unknowns to me, although the single Powercolor card I bought (a HD6670 for my father) is still running fine.