Only one that will fit.
My son is only 5 and his torso measured in at 10" and this is the only pack that adjusts that small, so my choices were somewhat limited. I liked all the other bags though, but didn't have a choice. That being said, he loves this pack. All he will be carrying is his bag and some h20 and toys that he may want on the trail. While some might complain that the bottom won't hold a bag, what do you expect from a pack this size? My sons bag fits great in the main compartment with his water bladder. He also has plenty of room for a few toys, or rocks that he collects along the way.
The fit and adjustment on this pack are pretty much the same as you would expect from any Deuter bag, and it will adjust with him as he grows. The materials on this bag are the same as you would find on many top quality bags. I would highly recommend this for anybody looking for a pack for their kid.