The 7D MK II I want. The 100-400sounds interesting, but not too interesting to me... However, I am sure than many will pick it up... The two lenses I see the most in the everglades are the 100-400 and some sigma X-500 zoom.
I'm saving my money for bigger glass... at some point... 600 f4 is more up my aisle. At any rate though, the 100-400 would make a good B-camera lens, for close overhead flights...