I rated this a 3, but that may be a bit high. It depends on what you wear inside the bag or if you use a liner as to whether the bag is decent. I used it this past weekend in WV with temps ranging from the low 40's to upper 30's at night. I was wearing a base layer and wool socks and I was still chilled. I have a fleece liner I made for it, which is super comfy, but I left it at home this time to save on the weight. The bag by itself should have been plenty warm being rated for more than 30deg below where the temps were, but I was chilled. When its cold I like to be toasty.

The Aether 70 is a great all around pack. I am just getting in to backpacking and spent a long time researching and trying on different packs (all said and done - about a year). I wasn't real sure what I needed, but after my investigation I went with this one. It is a comfortable and fairly roomy pack.

So far I have taken it with me on a 3-day trip in WV over very rugged terrain with around a 50lb load. The pack held up great. I was never unable to get the pack to a comfortable position. By adjusting the straps every now and then I was always able to get it comfortable.

I was lacking in the gear department on my trip so I used what I had - a crappy sleeping bag and tent specifically. I packed in a blanket for extra insulation (hey, it was a cold trip!). Because of that I definitely had "too much" gear. My tent, tarp, and pad were strapped to the outside, as was my jacket for the most part while we were on the move. The straps on the bottom and head pocket on the pack made it real easy to strap on what didn't fit inside. The pack still maintained it's comfort and balance very well.

The back panel is supposed to let air flow better around your back. It is much better than having the typical pad type back panel, however I found it to not cool very well. I worked up a good sweat hiking in a T shirt in 40deg temps. I would not consider this to be a drawback, just a heads-up to those expecting it to be an air conditioner.

I found the internal water pouch pocket to not be that useful. By putting my Camelbak in there I would have decreased the capacity in the main compartment and everything would push up against the Camelbak, pressurizing it quite nicely. I just put mine in the kangaroo pouch on the back of the pack instead.

One thing I will note, and a suggestion I will make, is I have the Argon hip belt and shoulder harness for mine also. These make a big difference to me. The extra padding makes heavier loads more comfortable. I will caution, though, that swapping out the harness/belt doesn't increase the load capacity of the pack as a whole. The suspension was designed to hold only a certain amount (as per Osprey's site it shows 50-65lbs as being OK). If you are in that weight range the Argon stuff will make a difference.

I stopped using suitcases/duffel bags when traveling. Now I just use my Aether 70!

For the majority of backpackers this pack will be a great choice. It fits real well, is balanced and comfortable when carrying decent loads, is a good price, and is very versatile.