Great bag.  JanSport bags seem, for practical purposes, nearly impossible to wear out, as I have abused one daily for over 10 years.
One reviewer complained of zipper snags.  Jan Sport has the best zippers I have used in bags, but, the zippers can snag on rare occasions.  If it does snag, it will very likely be on the curves, on the rain flap material.  In order to greatly reduce snags do the following:
1.  Flip the zipper rain flap material back, exposing the zipper around the two top bends in the zipper - you only need to do this once, as it will stay flipped back on the top, curved portion, and most of the lower portion.
2.  Align both zipper pulls on the upper left corner, just above the top left bend. (with bag front facing you).
3.  When opening, slide one zipper pull to the right around the right curve.
This procedure will greatly reduce snags, and make for a quicker entry and exit, as it will probably rarely be necessary to completely unzip the bag.