I bought one of these for my 40D, fitted it and hated the way it felt in the hand, can't really put a finger on what it was though, it fit real snug, did not slop around, did what it was meant to do! I just didn't like it, much prefered the feel of the bare camera. Also I wasn't convinced that it offered enough extra protection to justify putting up with the way it felt, I put it back in the box and put it on the shelf.
I do however keep looking at the box on the shelf and only a couple of days ago I thought I should try it again, thought as the 40D is now my backup to a 7D it might benefit from the extra protection.
I would see if you can hold a camera that is wearing one before you buy one as this is a very subjective item!
Hope this is of some help to you.
Edit I also use the 2 piece GGS screen protectors on my cameras and found them a good fit and easy to apply.