I have one (not an actual Camelbak, some other make) got it for about $30...it's a 1.5 litre, with a little bit of storage.
The straps are all mesh.
I've only used it once on a Big takedown where I was up the tree for 5 hours ( got lunch sent up on a rope) I have to say it was great, being able to sip a little, more often, was better than stopping for a big gulpy drink (what was that, climber sloshy someone said!) I barely noticed it was there, very comfortable.
The bite tube stays cleaner than taking the top off and on a bottle with grimy sweaty gloves...