I have just replace my camelback blowfish with this backpack because I heard good reviews on it. I have only taken it mountain biking twice, and several times hiking. This backup is great. I love its separate tool pouch, its pump pockets inside, and the mesh pockets for small electronics and keys.
The hard surface that helps it keep its shape and the bag close to one's body is outstanding. At times, after I have drank about half the water in the reservoir, I felt like I was not even carrying a backpak. Unlike my camelback that bounces around even when the straps are pulled all the way. It is smaller than the camelback blowfish, but I didn't need all that space anyway. This is a great design for mountain biking, but the using it for hiking did not pose any problems, so I recommend it for both uses.
I liked this pack so much (Raptor 6), that I got the Raven 6 for my wife. She has only used it hiking and reports with big grinning smile that she loves it. She was replacing a northface day pack. Once again, we like the fact that it stays close to your body and feels almost like a vest. The side hip pockets are a brilliant addition for quick access to snacks and even small electronics. HOWEVER, if it rains, the hip pockets are not a good place for anything that can get wet, as they are made of mesh that is exposed to the elements. I give it a 5 stars!