Ok, Where to begin...
I have not owned any other backpack sort of storage system for my camera (Canon 550d) hence this is my first experience. When I first purchased I was skeptical with the size of it, perhaps it being too large and bulky for ease of travel, but I am not having that problem anymore. This is not a small pack, and not a large pack, (Haha, not too helpful of elaboration huh). It is, as the photo shows, and I would say the best part about it, is there is velcrow inside the back which gives you the ability to create a more or less custom storage area. Currently I have the 550d with a 70-300 Canon lense attached, a Canon 28-55 lense, a Vivitar (bleh) fisheye lense, and a Sigma (yay) 50mm. They all fit in it comfortably and still there is more space! Once you open the main pouch you can have ease of access to all of your larger equiptment which would make it simple for quicker changeouts. The pack is padded which I find a big plus should you have to set it down quick and get out your camera or lense, you dont have to worry about breaking something. (given, you should not slam it, i do not believe it to be armor). There are various pouches on the inside and on the front which you would easily be able to store flash cards and other equiptment.
The only thing I do not like about it, is tri-pod storage. there are straps on the sides as well as the bottom where you can strap down your tri-pod, but my tripod is a larger (so to speak) one and strapping it horizontal on the bottom would make me too wide, and the strap on the (either) side is only one so it can be a bit wobbly, although secure. This is just my smaller nit-pick. It does what it needs to do (hold equiptment safely, and secure, which it does excellent)
I feel as if I am starting to sound redundant, so all in all, I would reccomend this to s friend, and I would but it again should mine ever get lost or broke.