Osprey EXOS 58 Backpack

Osprey Exos 58

I just got a new backpack.  It's an Osprey EXOS 58.  It weighs just 2.5 lbs!  My old pack weighted over 5.5 lbs.  While extremely light, it is much more versatile than my old one.    I had given up my pack top "lid" on my old pack to save weight.  I'm glad I get that feature back on my new pack.  It also has a pair of clips for hold your hiking sticks while hiking.
For more on this pack, see:
http://www.ospreypacks.com/en/product/superlight/exos_58

3-19 Update:  After a week on the AT with this pack, I absolutely love it.  All the pockets keep me organized.  The side mesh pockets allowed me to stash my Gatorade bottles while on the move and still hold my windshirt and/or trash I picked up on the trail.  The sleeping pad loops are a little short.  Just fits my RidgeRest.

Positives:

• Ice Axe clips hold my hiking poles when traveling. 
• Hiking pole Stow-and-Go works perfectly.  Great
• Putting one pole in the Stow-and-Go and using it to prop my arm while holding my umbrella worked great.
• Found that the lower Inside-out compression is best inside to not hinder putting my Gatorade bottle in the side mesh.
• Easily bottle to and from the side mesh pockets without missing a stride.
• Air Suspension back panel kept my back cool.

Negatives:

• Vertical access zips is really a pocket, not access to main bag.  Can be difficult to get stuff in these when bag is packed.
• Hip belt buckle seams a little small...  But working great so far. 

4-19-12 Update: Backpacker Magazine May 2012 scored the Osprey Exos 46 as most stable ultralight pack, and scored just below GoLite Jam 50. See http://www.backpacker.com/gear-review-osprey-exos-46-backpack/gear/16631

6-25-12 Update: Found a great review on backpackgeartest that describes the pack in detail:
http://www.backpackgeartest.org/reviews/Packs/Internal%20and%20External%20Framed%20Backpacks/Osprey%20Exos%2058%20Backpack/