Gigabyte is perfectly fine. Also, it seems that you are making an invalid comparison: one is a GTX 780 card and one is a GTX 780 Ti. Obviously, the 780 Ti is your better bet.
http://www.gpuboss.com
legend001523 has probably had a bad experience with a gigabyte card. Trust me, Gigabyte is a perfectly respectable brand, and the 780 Ti is superior to the 780.