Firstly, this backpack looks just like a regular backpack - it doesn't scream out 'camera bag.'
Camera gear stored inside is extremely well protected - the bag has tons of padding and, in fact, the backpack is quite rigid even when empty (it is the padding that does this). Mine holds a Nikon D80/lens with ease, even with the optional battery grip fitted. There are then 3 individual padded compartments, each of which being capable of holding a small/medium lens, or they could be amalgamated to hold a longer lens, etc. There are two further slimmer compartments, capable of holding flash etc.
There are 2-3 zipped compartments, plus a couple of small pockets for holding SD cards (or similar). In the top (non-camera) part of the backpack, it is possible to store your lunch and a drink - plus there are a couple more velcro pockets and organisers.
The backpack is very comfortable to wear and has heavily padded straps, plus a waist strap. There is a pocket on one of the straps for holding a small/medium mobile phone.
To be honest, it's hard to think of ways to improve this backpack!