only just found this, but here goes:
9/10
I have now worn this for two 20+ events, a 40 and a 60. It is extremely comfortable, breathes reasonable well on the back and easily accommodates enough kit for what I have done. (4 inns (mandatory only) and Fellsman (mandatory + extra food, 1pr socks, 1 tshirt). My only gripe is that to access the water bottles I have to swing the pack onto one shoulder, maybe I'm not bendy enough or need different bottles! I haven't utilized the bladder yet, as I usually keep my emergency blanket, maps and overtrousers in that pocket! However I will give it a go over the summer, if it works out I think it would be a 10/10.