I am totally familiar with American Tourister. Since at regular intervals I have to buy a backpack for my student designation. I am totally satisfied with their qualitied product. First of all the material they use for making backpacks are too good so that it will definitely last.
Next is the zip quality. It has never made a problem for me. So I had never a chance to go to the sewer.
It comes in variety colors as well as variety designs as required by a teenager. So I love it. But it lacks in waterproof feature. So as the price is affordable you can add such a feature also.