The gigabyte supports more OVERALL USB ports as well as faster RAM speeds over the Sabertooth from the specs that i gathered.
Both also have (2) x16 PCIx slots for running SLI. by the looks of it other than a few USB ports and the extra memory speeds that the gigabyte offers over the sabertooth they are pretty much the same boards.
I think that's the P55 version dude. The x58 only has 4USB port in the back, plus the USB 3.0 ports (2 i think?).
It does have, however, 10 Sata ports with the 2 new 6GB/s ports. (2 more sata ports than the Asus =P) Amd the Ram Specs are correct - highest Gigabyte can push is 2200Mhz compared to Asus's 1866Mhz. (Though @ 1600Mhz, either one works fine).
And Warranty wise, Asus has 5 years compared to Gigabyte's of 3 years.
I did find a website that compares the Gigabyte with several other good mobo's (Asus Rampage III, Asus P6X58D Premium, etc.) but sadly not with the Sabertooth. Still it might help some =)Here's linkey! xDD