We've carried the Atmos and Aura packs since they came out back in 2007, and WOW have they come a long way. About the only similarities now are the suspended mesh backpanel and the main lid. Everything else has been redesigned from the ground up for a better fit and superior load carrying. The most notable new feature extends the suspended mesh out to the hipbelt and up the shoulder straps in one seamless, body-hugging piece. Combined with fully adjustable hipbelt padding, this is one of the most comfortable packs we carry. It is a bit heavier than the original pack, but the weight penalty is outweighed by the awesome fit and load control. Ounce counters will probably want to go with the Exos 58...another exceptional Osprey pack. On the subject of fit, I should mention the Osprey "Fit One the Fly" system that -- as the name implies -- allows you to fine tune the fit of your pack in a few seconds without the use of any tools. The hipbelt and shoulder straps are pretty self explanatory: slide the padding in or out until you're satisfied with the feel. Slightly more complicated is the torso adjustment...you'll have to reach under the mesh to find two sliding plastic toggles. They release (with some gentle convincing) and allow you to move the shoulder strap system up and down as precisely as you need. There is a LOT of adjustment room on this pack. The lid will look familiar if you have experience with Osprey Packs, but what's not familiar is the minimalist lid hidden underneath. If you remove the main lid you'll lose out on two additional pockets, but you'll save some weight and bulk. The side by side photo at the top of the page shows the "Absinthe Green" with the main lid attached, and the "Cinnabar Red" with the main lid removed. The minimalist lid is by no means ugly or flimsy, it's purpose built and even includes the Osprey logo in the right spot giving it a nice streamlined look. The side compression straps route nicely around and then behind the side mesh pockets, so you can make full use of the pockets without loosening or fiddling with your compression straps. However, you can slide larger items under the compression strap if you need a more secure option. You can see an example of reinforced construction in the photo of the side pocket. The compression strap isn't sewn into a seam, but rather into a corner of folded fabric. This spreads the tension over a large area and really beefs up the durability. These sorts of sewing tricks can be seen all over the pack. It's easy to see why the have the "All Mighty Guarantee" for their whole pack lineup. If your main priorities are comfort and durability, this is a pretty lightweight setup for an overnight or weekend trip. It's not for you if weight is your first consideration. There is a wide selection of crazy ultralight packs out there to choose from. For most though, a simple lightweight, comfy, and durable pack like the Atmos is just fine.