I would also go with a mix and match, using build 1 as the base.
Put the GPU from build 2 into build 1 and you are set with the best gaming computer
Possibly also the PSU since 750W is not enough for 2x 6970, and 650W is just fine for one.
As for which one has the actually configured ones has better value for gaming. That is build 2, because it comes with the 6970.
And other parts are still quality parts. But yeah, if you can do the suggestion on it, that will get you the best performance for gaming.