Here's what I said about it in April:
I bought a new daypack this year too which I'm very excited about. The model is an Osprey Stratos 34. Osprey makes the best backpacks, period. They think EVERYTHING out. The only question is if the model you're looking at had what you intend to do with it in mind. I'm not 100% sure this one does, but Osprey guarantees everything 100% no questions asked forever, and so does REI where I bought it with my annual membership coupon. This thing is replacing my smaller, less comfortable, overbuilt, less intelligently designed Maxpedition "pygmy falcon" pack, which was tough and had nice water bottle pockets, but... well that's about it. The Osprey, while more delicate, has a taught suspended mesh backpanel which keeps you much, much cooler and drier when hauling ass up a hill in the Sierra sun. And it has a good waist belt to put the weight on my hips where it's not going to F-up my back... that and a whole bunch off other things that Osprey does right.
Unfortunately it didn't pan out as well as I'd thought. The primary problem was that the wire frame dug into my hips / lovehandles (I'm 5'10" 155lbs so it's not really a fatness issue)... No amount of adjusting would really fix that. The design was curved too much I think. Sure my back didn't get too sweaty, but it put the weight too far back and too low in the pack so it ended up torquing the load (read frame wires) into my hips, to the point I'd often come home from big mile hikes bleeding. It's probably fine for people running lighter loads, but I carry tools and survival supplies for work and so anything over about 12lbs started to suck.
It was also a bit difficult to load and organize. The outside pocket intruded onto the interior space as you loaded it rather than expanding outward, the top wallet and keys pocket was always in the way when accessing the main compartment and the heavily curved space of the main pocket which was further intruded upon by the outside pocket made it a royal pain in the ass to find anything. Plus it just didn't open very wide.
The buckles on the iceaxe holder were also flimsy... way not strong enough to hold larger tools, ie. axe, pick-mattock etc. Nor was it adjustable.
Also the pack cover it came with was bright fricking red. I bought the neutral "slate" color for a reason. Though I suppose that cover would be useful in an emergency for signaling or marking an LZ. Maybe Osprey ought to look into two-sided different color rain covers. Black on the outside, bright red or yellow on the inside for signaling.
I like Osprey, I have and love 2 other packs from them, but this one's a stinker (for me).
So I've stacked up black friday sales and coupon codes and ordered a Mountain Hardwear "Splitter 38". It's a cragging pack so it focuses on organization. My back's going to be sweaty, but at least I can organize the living shit out of the load. It's also a bit bigger. That Osprey probably would have been big enough but the space was just not that usable. I seriously considered the Gregory Z30 as it solves a lot of my needs and doesn't have the "brain" that I don't want, and still has a suspended mesh, but it's a hair small, and I didn't like some things about the organization system in there. Most people carry clothes, food, water and a first aid kit. I have tons of other stuff and I'm in and out of my pack a lot so I guess I'm going to pass on the suspended mesh for now. Shame, because I love it in my Osprey Exos 46 ultralight (but fragile) backpacking pack. Anyway I'll try to give an update on the new one after I get some field time with it.
Right now I'm getting really antsy to do some winter camping and get my system for snow dialed. But it's been pretty slushy up on hood still. SOON!!!!