My 100-400 is challenging me to get clear hand-held shots (on 7D). It's me, for sure - every now and then I do get sharp images. Maybe I should just give it some more time. Bought a good monopod too, that could help. No clear question here, just inviting comments. I'm frustrated because I had a pair of pileated woodpeckers in my back yard last week and didn't get one single clear shot. Not much time to practice.

I, too, was very challenged learning this lens. Still am. The monopod improved my shots considerably. Keep practicing. sample attached, on my second time out with a monopod. Not perfect by a long shot, but much, much better than hand held. Good luck!