not much difference with 780 other than 3way Sli, and totally useless if using a Q6600 you wont get more out of it
45nm cpu support, Native PCI-e 2 support, DDR3 Ram support, and tweaks here and there that allow it to overclock quads higher than the best 680i boards. They are a worthy replacement to the old 6 series and if you plan to run SLI with the latest cards there the best choice.
There are countless people that have managed to get the G0 stepping Q6600 to hit 4GHz with their new 780i boards.