Osprey Exos 34 Large

I recently received the Exos 34 & had my first opportunity to use it on a day hike, though I had it loaded with the gear I will use on a 4 day hike on the AT around Labor Day, including food & water. I currently own a GG Mariposa Plus & Gorilla but find they are both uncomfortable during warm weather use here in the Southeast. I sweat profusely & wanted to try the Exos with its ventilated mesh back panel.
I had not seen a review of the Exos 34 as everyone seems to either use the 58 or the 46 models. The 34 easily held my Golite Ultra 20 quilt, NeoAir sleeping pad, Tarptent Sublite, Caldara Cone alcohol stove with Snowpeak 600 mug, rain jacket & pants, bag with a change of clothes, 4 day food bag, 2 liter Platypus Hoser, Katadyn Hiker Pro filter, headlamp, & toiletries, etc. The 34 was still not quite full! I can't imagine why a lightweight backpacker would want the larger models.
The 34 carries very well & was cool against my back. The hip belt was comfortable & the mesh pockets on the belt were large & useful. The various other pockets are well thought out & useful. The reason I didn't give the pack a 5/5 is that I couldn't easily get my water bottle into or out of its side pocket while wearing the pack. This is why I chose to use my hydration system instead.
I will update this post after my 70 mile hike thru the Great Smoky Mountains Nat'l Park in 2 weeks.

Addendum, 9-10-09
My rating remains 4/5 after my 71.6 mile thru hike on the AT in the GSMNP 9-4-09 thru 9-7-09. The Exos 34 remained very comfortable & cool, as it had previously, despite 3 consecutive 21+ mile days & 8 miles on day 4. The hip belt required occasional re-tightening but this was no problem.
The Exos easily carried a 4 day gear set as noted above. I did not carry a tent due to the rules of GSMNP but the Exos could have done so. My down quilt could have been easily compressed to 1/2 the size at which I actually carried it.
Again, the only problem found with the pack is difficulty getting a water bottle out of the mesh side pockets. Perhaps steeper angling of the pocket tops would accomplish this as well as a looser elastic band top.
Overall, the pack meets my expectations & will be my "go to" warm weather pack.