I only like the third one because of the effect. If you executed the effect better and made a better background, you could make a very good shot. And only put one spartan in a retake. 2 doesn't looks good for that effect.
As it seems is the obvious favorite, I too like Gradient the best. This is purely for the effect however.
I'm not quite sure how I got the effect in gradient... I found this room in avalanche out of the map and weird things happen in there. And the first one wasn't staged, that's why I like it.