I've had one... It looked good but the buckles on the back made mincemeat of my coats and jackets. Someone pointed out to me that there was a threadbare patch on my (favourite) coat, and I checked my other outer garments and found that the same thing had happened to all of them. I don't know whether this is a common problem with backpacks as I haven't had any other brands.
Also, it was a bit stiff and unwieldy for me, but that's probably because I'm a 5ft petite and could have done with something a bit smaller.