acoll, I understand your original hesitation. I've seen shots using the original 70-200 f/2.8 L IS with extenders and the lack of resolution is fairly obvious and distracting. if you're using a 7D, I'd consider just getting the EF 1.4x III as that will still get you up to a 448mm equivalent on full frame, and the sharpness at f/5.6 will be excellent. one stop down from max aperture seems to do the trick with the new extenders.
branden, glad the review was helpful. I'm basically planning the trip through a lot of research. normally when I travel abroad I just get a guide book, plane tickets, and book a hotel. since going to the galapagos is a bit more involving, my wife and I decided to stick to well-known tour operators. we're using Gap Adventures (http://www.gapadventures.com/
) since they're reasonably priced, a large outfitter, and allowed for a number of options in terms of how you structure your trip in terms of destinations and also pricing level. I'm very excited about it, feel free to PM me if you have more questions.