Looking at getting rid of the sigma 150-600 and replacing with one of these two combos as with a trip to the Galapagos coming up weight savings are a priority. Losing some reach with the 70-200 option but getting a more versatile rig than the 100-400 and being that it will be mounted on a 7d2 I am guessing it will suffice as distance to wildlife in the Galapagos should not be an issue most of the time. Any oppinions on the best option from those who know?