In reply to garethtodd:
I've got one. It's alright, but a bit on the small side of 45l. (I know that sounds non-sensical, but I'm sure not all 45l rucksacs are equal!)
I find the back, waist and shoulder straps comfy, but the lid really annoys me. It doesn't cover the top of the bag very well when its full and the pocket in it is really small. You struggle to get an OS map in.