I was looking for a backpack that I can use for both day hikes and for backpacking (I pack light when i go backpacking!). This pack is extremely comfortable, and has the perfect amount of storage for carrying all my gear. It has a sternum strap (which has elastic so it doesn't constrict your breathing), and a waist strap. padding on all the straps, and the padding on the back of the pack itself, is plenty comfortable. There is a phone/mp3 player pouch on the left shoulder strap, and the top of the pack has a special thru-hole for use with a water bladder.
My only complaint is that the zippers are a bit tricky to use. The zippers seem pretty durable, but it can be a pain in the butt if you have to unzip and zip the pack frequently. I think other reviewers pointed this out too. It isn't a deal-breaker, it's just kind of annoying. There is a fabric strip that covers the zippers (like most backpacks have), and if you pull it away from the zipper before you try to unzip the pack, it is much easier.
As far as capacity is concerned, I am able to fit all my backpacking gear (sleeping back, tent, food, fishing gear, etc), my full-size camera tripod that collapses to 15", and two 1-quart bottles in the mesh side pockets.
My backpack is still good as new after 3 years, and I even use it as a carry on bag at the airport frequently, however the carrying handle on top tore off about a year ago. It didn't cause any damage to any seams or anything, so I just cut off the remaining material for the handle and continue using the backpack without it. I do miss it sometimes though, it was a great place to grab hold of the bag to toss it into my car trunk. If the rest of the bag ever bites the dust, I will definitely consider buying this exact same backpack to replace it.