In reply to neuromancer:
I've had one for this winter season so far. I've used it for winter climbing, rock climbing, skiing, and a short train trip to London. Its a great bag. No holes so far, the axe attachment is refreshingly simple (why do we need fancy complicated not-very-secure easy-to-break axe attachment points Osprey? stupid...) works well for carrying skis, the zip is tough and useful once you get used to it, and the bag gets wider from bottom to top so its easy to pack efficiently.
My only issue with it is that the straps that hold the shoulder straps to the back often get caught under the lid, then the straps loosen up and the bag is hanging miles backwards at the top. its fine as long as I remember to check it after doing up the lid, but it can be bloody annoying, especially when on an awkward stance in a gale!
I find the back and the waist belt comfortable, though I've mostly been using it with a lot of layers. I guess I'll find out more when I use it this summer in California.
Overall I'd totally recommend it, as long as you don't like fancy (IMHO useless) gadgetry on your multipitch bag. (I do have an Osprey 70 L for long backpacking trips and I love it for that because it has an amazing back support, but Osprey make their bags too complicated for winter)