Great little pack!
I got this pack because a girlfriend of mine had the 18L version that we used for stowing our climbing gear, which worked well with the rope strapped over the top of the bag (The bag unzippers WIDE open, so you can really jam it full of stuff). Also one of the other reviewers stated that front straight jacket style straps are perfect for holding snow shoes. This sold me, and when I saw this on SAC I couldn't pass it up! And dude was right. It holds my snowshoes and poles perfectly along with hydration bladder and random stuff. I'm sure it will function great this spring for holding my climbing gear since the 18 did such an admirable job. Yes the large vented back area seems to reduce carrying capacity upon initial inspection, but when its 85F and humid out and you're carrying your gear to the top of the cliff, you'll appreciate that its there! Also, you can easily fill this hollow area with small odds and ends that you don't want to have crushed in the main compartment. It's a great little pack! (Oh, I'm 5'9" 170lbs 32" waist, I purchased the medium.. in black, because the other two colors are a little too flamboyant for me)