I have the gigabyte one, but 4gb and rev.2 edition.
Spent a hell of time on reviews about which one to pick, i also installed yesterday the Asus one on a friend's system and tested it, so i have experience on those 2.
But i know as fact,
Gigabyte (if u find the rev.2), very quiet and cool, 72 celsius at load and still you cant even hear the fans.
MSI, maybe the best cooler on a 770, ugly pcb (brown)
ASUS, kinda noisy at load, kinda hoter, very good looking, the only one that has a backplate.
Zotac and Palit is out of question for me, i dont trust those manufacturers. Used palit's cards on the net cafe i work on and i didnt like em.
Now, the choice is yours dude