In reply to biscuit: I have the Grivel, and it's fine for general cragging use, haven't really used it for much else though. The back system is really comfy even when it's pretty heavy (2 ropes, 2l water. HUGE rack etc.).
It replaced a Marmot pack which was horrible to wear and I'm really happy with it. I would happily use it for multi day camping trips etc. if I hd the need.
If the weight is an issue you could probably cut off a lot of the extra features and remove the liner.
The Osprey looks cooler though...