If I was you, I would not go for amd at all. The future is intel. I know they cost more but that's why you have less problems with heating and other errors.
Since 2008 I am not using amd nor ati hardwares. With intel you have less problems.
Huh .. wtf. Heating / Errors?
Don't want to get into a debate here, but everything you just said is textbook definition of a fanboi. AMD's haven't "overheated" for over a decade, and I've ~never~ heard of "errors" happening in the entire time I've been building systems (over 20 years now).
Anyhow, to the OP, Both the Sabertooth and Gigabyte perform the same, their both Tier 1 manufacturers and have solid warranty / RMA systems in place. Honestly go with the one that has the better layout or feature your looking for, other wise their the same.