I just got back from a trip to olympic national park where I rented this lens. Lots of photos to process to get them up here, but they'll come!
The lens was phenomenal. 560 isn't as long as I though it would be on full frame, but still more than I've ever had.
The IS was amazing. On a monopod I got sharp shots at 1/30 at 560mm.
The wildlife didn't cooperate as much as I wanted but I got a few keepers. However the creative uses and telephoto effect allowed some fantastic landscape shots that really capture the grand sizes of nature surrounding olympic national park.