This backpack fits my 5'4" frame as well as my husband much broader 6'1" frame. And it's easy to adjust it back and forth between the two of us. My 9 month old son LOVES riding in it - great view of the world. It's much easier to wear/carry than I expected and lighter.
I would definitely recommend getting the sun shade to go with it - we don't have yet but will buy it. He's a little too exposed to the sun without.