Well... it depends.
The Gigabyte board is based on the P45 chipset, and the board supports two-way ATi CrossFireX.
The EVGA board is based on the nVidia 680i chipset, which supports three-way nVidia SLi.
It's really hard to say which one's better... but what I said above might help decide.
The 680i is meant to be a high-end motherboard, whereas the EP45-DS3R is just a mainstream one.
I'd say the EVGA one.
nVidia's chipsets aren't exactly the most reliable however.