In reply to steelbru:
> (In reply to Aly)
> I'd definitely ensure that there were pockets in the waistbelt so you can get at stuff "on the move" eg gels, gloves etc. You don't want to have to stop and take the sack off to get at stuff, because if you're anything like me you won't bother to save time then end up not performing as well, or getting cold hands, etc.
Very good point - pockets in the waistband are really useful.
Something else I've learned to look at is the shaping of the shoulder straps and the likelihood of them rubbing on the neck. I have an OMM 8l sac, and it's fine apart from the fact that the straps rub painfully against my neck. I've found that one way round this is to run in a t-shirt with a collar (a zipped t-shirt), so there's a layer of fabric between the straps and my neck. Still not quite ideal, but it's better than being rubbed raw.