about your question of other options or brands of the HD 7850 Gpu , there is the SAPPHIRE
SAPPHIRE HD 7850 OC 2GB GDDR5
Is it any good than the gigabyte? considering that it has lower clock "920 MHz Core Clock"
7850. Definitively. See if you can find this card http://www.newegg.com/Product/Product.aspx?Item=N82E16814127663
Also the performance for nvidia optimised games like bf3, diablo, cyrsis 2 etc may dip. If those are your games of choice, then the 560 ti (esp the twin frozr hawk edn) isn't really a bad option.