Well, went and bought one of these and my thoughts so far:- (Woodland camo version)
* Good size, I can fit all my hunting gear IN it (Coat, combat pants, hats, gloves, lamps, batteries, pellets, targets, lump of wood for zeroing - you name it, its all in the bag)
* Straps - hmmm, these come in S,M,L - if you are XL - I am not sure how well this thing will fit on your back!! I have extended mine and it is comfortable with a t-shirt, jumper and jacket - IF I don't try to fasten the cross chest strap. I don't feel like I need to, as the shoulder straps keep the bag in place fine.
* Waist st