What you got in the links above is the Gigabyte Stock model (Overclocked) and the Gigabyte G1 Gaming model.
G1 Gaming is superior to the stock model as it has many features listed here:
http://g1.gigabyte.com/vga/feature1.html#WINDFORCE
In addition the G1 Gaming is also factory overclocked (Might be wrong), both are great cards and Gigabyte is a great brand, I have an old Gigabyte GTX 560ti that still runs like a champ, now I have a GTX 780 EVGA (Also a great brand), if I want to upgrade now I would go with Gigabyte again, its one of the leading brands nowadays selling Nvidia cards.