Hey Wrath, I was considering the same question.
It generally boils down to how much you want to pay and what you want to use the board for. The Asus is more expensive but it a better overclocker and has few more extra features. The Gigabyte is a lot cheaper but doesn't overclock as well and doesn't have the extra bells and whistles.
The Asus also supports only DDR3, whereas the Gigabyte has 4 slots for DDR2 and 2 slots for DDR3. By the time that DDR3 comes down in price though, I'm sure that there will be better DDR3 motherboards coming out.
If this is the case, then there's the Gigabyte GA-P35-DS3R and the GA-P35-DS3P. The GA-P35-DS3R doesn't have the DDR3 support, as doesn't the GA-P35-DS3P, but the DS3P is an upgrade of the GA-P35C-DS3R you queried in the post.
It's just not complicated enough is it!