My first roll top bag was an Overboard backpack, which is an awesome bag, and the reason I got the DryPak.  The bag is a water proof as it gets, and the quality is just as good as the Overboard.  The size is what sold me as Overboard did not make a duffle in this size, but I must say that this thing will hold a lot of stuff. Be forewarned that it will be a heavy bag when fully loaded.  I plan on using it for everything, and it will be my only luggage.  I plan on getting a cheap hand cart for hauls from the terminal.  Very well made.