Excellent quality and design
just got back from a day hike and conditions were rainy and humid. The airflow system works as advertised; no sweaty back! The built-in rain cover came in handy as well. I like the separate compartment which is perfect for my SLR camera. The main compartment was plenty big for extra water and clothes. The quality is top notch. This is THE pack to get in this segment!

Well worth the price
I primarily use this backpack for commuting to work on my bike year round. Whether summer or winter. I've always worn light weight/breathable clothes but I could never escape the inevitable sweaty back when I got to work, (even in the middle of winter) so I invested in a Deuter. The pack was bigger than I expected, and also sits higher on my back than I expected, but you get used to it. Works well for carrying a full change of clothes, thermos, lunch, plus room for other stuff like a box of cereal. I often take a 20+ mile ride after work on my way home and I've yet to have a sweaty back. This pack will be good for weekend getaways, too; but if you just want a tiny pack to carry just a few items I'd recommend the Race X Air. I got this pack over Lowe Alpine's Airzone (yet both are well made)

Not my choice for cycling but a great bag.
I commute 35 miles daily on bike with this bag and while the suspended back allows optimal airflow, you cannot tighten this bag to sit tightly against your back. This is because of the plastic support that supports the airflow system. Other than that, it's a great bag for walking.

Good quality and design
I like this backpack and really like the breathability of the design. I haven't had it at the field yet but will be taking it out soon. The pockets are arranged well and I really like the built in rain cover.