This is by far the best day pack I have owned. The size makes it a super versatile pack. I have used it for traveling overseas as a carry-on, camping, backpacking, and cruising around town on my bike with groceries. It is unbelievably light and super comfortable.
I used it this winter for an overnight snowshoe trip, and it was almost too small for all my gear. Even though I packed it to the brim and strapped some gear on the outside, it seemed to handle the load just fine without too much sloshing. It stayed firm on my back and comfortable.
I use the Atmos 35 as my carry-on when flying, and it fits in the overhead compartment perfectly. It does not, however, fit under the seat. The pockets are all placed nicely and the top load main compartment is nice and roomy with zippers that unzip all the way down so it is easy to get to your gear or laptop.
If you are looking for a good all-around pack and don’t need too much capacity, I highly recommend this one.