Overall for the price compared to similar items it is good at it's intended purpose. Also compared to another backpack pet carrier I tried, this one does not hurt or have any structure that digs into my lower back.Improvements:Better structure-the sides and top easily collapsed with any force; I had to spent some time repositioning the edges to get a more solid structure and for the zippers to close; there is still some corners where I need to wiggle the zipper to close or open.The bottom base of the backpack is sturdy and has a nice fabric covering, but some more padding would be nice with a removable/washable cover.There were some stray threads upon opening and the top zipper mesh window was broken, but easily fixed by opening and closing from where the zipper was, but questionable quality.The one roll up window on top could have better placement of the velcro so you can do a tight roll and have the full view of the top.Except for the base zipper, none of the other zippers have any locking mechanisms.There could be more padding in the shoulder straps and a waist strap could give some more support.Strange the front wheel on the base is removable and the others are attached directly to the based. The front wheel is also slightly smaller than the others, in that it does not touch the floor with the other wheels when on an even ground. Seller stated "The front wheels are mainly for support to prevent the pet bag from skewing. If the wheels are the same length, it will not be smooth when pulled."When I used it I had to wheel the bag sideways, the front window facing outwardly perpendicular to the direction I was facing, as that is how it wanted to go naturally, which made it uncomfortable to move w/ the handle.It would be nice to have an option of the expandable backpack paired with the removable wheeled base.