For the past year I have steadily reduced my pack weight from about 45 pounds to around 30 pounds (weight includes water, tent, and climbing gear). This pack has helped me do that. The Bora 35 is perfectly sized for 1-2 night trips into the backcountry for those of us who pack light. I am sure I could have made it a whole week (though 2 nights is the longest I have used it for so far). What gear wont fit in the main compartment can be latched on the side or under the lid via compression straps. Arcteryx also sells an accessory pouch which fits on the side straps that helps keep your clothes and smaller stuff from just floating around in the bag (it adds 6L of space).
For those of us climbers looking for a camping/climbing bag in one, this is it. After unloading it at camp, stuff the rope into it the way you would a haul bag and clip all your equipment to the daisy chains down the back. Now you are ready for everything from top-roping sport routes to multi-pitch trad climbs.
The waist belt (which can't be seen in the picture) is just a 2-inch nylon strap, which sits high on your hips. The purpose of this is to allow it to be worn along with a climbing harness. I have used it this way, and it works out great. Just don't expect a nice thick hip-belt to help you with the weight the way the other Bora packs do. Like I said, this bag is great for 30 pounds or less.
The waterproof hydration pouch can hold a 3L camelbak bladder just fine and the main compartment can stuff a 70m, 10.3mm rope from end to end to help you move quick between climbs.
All in all, the perfect bag for those of us weekend campers/climbers who know how to pack light.
One last thing- I'm 5'10 and the Tall size is perfect. You can look up sizing info on the the Arcteryx site, as well as the accessory pouch.