We have a crysteel where I work and I agree that it is nice. We don't have the drop down sides, but it does have the 'quick' release tailgate, which so far has worked flawlessly. As easy as opening a truck tailgate. As for durability, I guess only time will tell.
Myself, I have a 12 ft rack body dump, that I have been extremely happy with. Just have to be careful of those 'crazy' loaders at the supply yards who try to fill the whole thing up. The other day, they dropped 10,000 pds of topsoil on my truck and the gvrw is only 10k.....oops.
My next truck will be a drop side model. I'm looking at either a crysteel or maybe one of those new stahl's. Anyone have any experience with the new stahl dump bodys that have the 'smooth' sides? They look real nice, and they have a side drop option, that comes in handy for loading my truck with a dingo.