I've bought quite a few IST damaged books. All the damage has been on the outside, nothing wrong with the pages. The majority of the issues are extremely minor. I couldn't even figure out what was the matter with some of them (like the Vision TPBs). But it's still a bit of a risk, depending on how much you care. Here's an album with some examples.
Absolute All-Star Superman - I can only assume the issue is a tiny, tiny bump to the upper right corner in the picture.
Absolute Batman Incorporated - A small crush to the lower left corner.
Crisis on Infinite Earths deluxe - The dust cover seems to have been cut a little off. No matter how much I align it, one part overhangs a bit and another part shows a bit of the hardcover. It was in shrinkwrap, and even before opening you could see it didn't look quite right.
Saga Vol. 7 - Just a bit of a bend in the corner.
Black Science Vol. 3 - A scratch across the back cover.
Rat Queens HC - A pretty significant crunch in the corner.
http://imgur.com/a/kKvEb