I waitied an interminable time for this lens to arrive and when it finally did, it was pouring rain outside. My initial shots were indoors which is hardly a fair place to test a lens like this. Regardless, the results were fantastic. Super sharp as it should be and very good IS.
My only complaint is that the IS/AF is noisy. Not mildly annoying, Noisy like elves are moving heavy furniture inside the lens. I thought that I might have a problem with the lens but when I compared it to another copy at my dealer, it made the same noises as well. I'm going to wait for the Canon rep to come to the store and see what he thinks, but int the meantime, I'm very happy with this purchase.
I would easily recommend this to anyone who wants a super sharp medium telephoto.