Juan Carlos M.wrote a review of JanSport Duffelpack - 2400-3600cu in on January 13, 2012
I use this primarily as a gym bag. It's able to hold all of my gym sundries and has enough pockets to keep my small things organized; wallet, phone, watch, etc. It's also small enough to fit comfortably inside a small locker.
The only nit I have with this bag are the straps. I suppose it sounds good on paper to be able to wear the back as a backpack but the flat straps aren't very comfortable and you can't shorten the straps enough because the buckles get in the way of the pad.