To me, quality of Galaxy cards is just as good (no better and no worse) as the others (my personal experience is limited to Galaxy, Asus, Gigabyte, Inno3D, MSI, XFX, Sapphire and HIS....). I more or less follow this company from its earliest days because many of my cards in those days were Galaxy ones (Riva TNT2, GeForce4 Ti 4200, 6800GT).
Galaxy gets my appauld for being aggressive in innovations (eg the flip out fans of the 470/480, the single slot 60, GTX460 White Edition/Hall of Game, the GTX460 WHDI...etc)
To me, the deciding factors are more like local warranty and customer support, price of the card and what extra features come with the card.
The company is well established in Asia and is expanding its European prescence in recent years. I suppose you are in North America and so have not heard of this company much? And warranty varies globally.
North America support link: http://www.galaxytechus.com/usa/support.aspx
It seems they recently add a toll free number for customer support in North America. Perhaps you can call it up and just talk with them to test out their customer support in your country?
PS and I am not a Galaxy fanboy
. I recently got Inno3D's GTX570 in lieu of a Galaxy one because it is factory oc'ed and has more extra stuff bundled.