Good volume to hold your gear if you're getting into ultralight backpacking. The two mesh pockets on the sides securely hold nalgene bottles. the large mesh pocket on the rear has enough room to hold my rain gear, tarp, stakes, and ground cloth or bivy. The interior has a hydration sleeve that works well in holding standard platypus containers. For weekend trips in three seasons I don't take along the top lid - don't need the volume. Some people complain about the top lid falling to the ground when you open the pack, but there is an easy fix for this -  Go Lite Trek Pack Lid Fix.

Straps and belt are very comfortable with a more than full load. I do have some problem with the plastic fitting holding the chest strap to the pack strap rubbing on the inside of my arm when my arms swing and the chest strap is not fastened, but this is probably just the way I am built and I have a fix for it.