I purchased this backpack for a trip to Europe this fall, but just tested it out in New Orleans. I love it because it aligns comfortably with your spine and it has A LOT of room. I filled it up with 2 weeks worth of clothes, shoes and toiletries. It has compression straps to eliminate some of the bulk and side pockets for easy access to small items. The 55 size is perfect if you plan to use it on a long backpacking trip.