Good for commuters
Bike commuting? Go with the Race X Air II - it gives you more room but not more bulk than this one. As a woman commuter finding a bag was tricky but I'm very happy with the Dueter bags - the web panel on the back acts like a trampoline keeping the contents of the bag off your back. This is a great feature for people who tend to overheat like me. I was worried the shoulders would be too wide since Dueter makes women specific packs but found this to be a good fit. The bag is really light and almost impossible to pack completely full (the Race X Air II that is). The downsides to this bag are the zippers - they don't open the bag up all the way. This makes it difficult to air the bag out after storing your sweaty commuter clothes in it all day. However, the fit and the back cooling system are unmatched in the other bags I looked at so the zipper gripe is minor.

Great pack
We used this on a recent trip to Disney world and plan to take it on many hikes this summer. The water stayed cool and was great for storing a few snacks and a lightweight jacket.

Great but not perfect
This is my second of these packs. Two features attracted me to them in the first place: The web panel that holds the pack away from your back, and the web shoulder straps that breath or let air thru. Both of those features work! The new Race X that I just bought has a different 3 lite bladder and it is a good one. Better than the one in the first pack I bought which I replaced with another 100 oz name brand bladder. This new Deuter bladder has a wide mouth fill opening that has a fold-over closure with a sliding clip. It works great, easy to use, allows cleaning the inside, and it doesn't leak. The only problem I had with the first pack, which by the way I used hard mtn biking for probably five years, is the zipper on the smaller compartment died. If I was king I would like bigger, beefier zippers. The zippers Deuter uses and too light weight in my opinion. I just bought the second pack so I guess it was not a deal killer. The new pack also has two mesh side pockets that the first one didn't have and that's a handy feature.

Cooool !!! And Functional for Mountain Biking
This pack is perfect for longer rides. Holds 100 oz. bladder plus 2 20 oz. Lifeline slim style water bottles wuf wuf. This pack keeps your back very cool and is comfortable. Side mesh pockets hold plenty of energy bars. Helmet holder works great for rain jacket. Outer pocket 1 tube, tools, keys, wallet, misc. parts. Main pocket fits pump and other smaller items camera & phone. If your into packin more stuff get the race x air 2 it has more volume and padded straps. The zippers on these packs are very durable. I have 2 older dueter back packs that are still going strong 5 years. I use them alot 2-4 days a week. I'am a extreme mountain biker and advanced hiker. Well worth the money!!!

Nice pack for commuting
I bought this pack primary to carry my notebook PC and few clothing items on my 15 mile daily round trip biking to work. I don't use the hydration features (never have figured out how keep the hoses clean on any hydro pack). The mesh suspension keep my back much drier than my old pack. the fit is comfortable. My only minor criticism is that a tiny bit more width and my 14" screen notebook would fit perfectly...it's a bit tight, but it works. Workmanship is great...I've used it almost daily for 3 weeks now, and its become part of my daily routine.