It's a great bag in overall. I love that it has so much space (if you have only one SLR + one lens then you may consider buying the SMALL one.
However, I have problem with the zips. They're so difficult to open / close. Probably it's a part of the bag closing system so that it's not easy to open a.k.a. camera falling out from the bag accidentally, still it's irritating when you have to spend a few minutes struggling with the zip just to get the bag open.