First off, I've been very happy overall with my Duluth Pack.  It hasn't given me any serious difficulties and has over all been incredibly useful. There are a few outstanding features:

1. Great canvas and leather construction.  I can swing this thing around and throw it on the ground and kick it, and there is no problem with integrity.  So far I have taken it to school full of books all semester, and then to a convention, and used it for everything from board games to boots and it's held up fantastically.

2. Tied to that, it's very easy to clean.  Just use a damp cloth or even a light scrub brush like a nail brush for flecks of mud.  The canvas is nice and sturdy and holds up well and doesn't discolor.

3. It's very understated if you get a neutral.  I got this pack partly because I saw one of my fellow teachers carrying around one of those sporty looking mesh backpacks and thought, secretly, that it looked pretty unprofessional.  Handcarrying a briefcase is almost impossible when one of your textbooks weighs about 10 pounds, so a backpack is necessary - but I really prefer this rugged, grown up looking pack to the neon and polyester variety.

4. It's very secure.  You can zip your wallet right into the little interior pocket, buckle the straps and nothing will fall out.  Heck, even if you don't buckle the straps, as long as it isn't stuffed, you're in pretty good shape.  I like the somewhat deconstructed style here, not super boxy, but it really doesn't just collapse like a sack either.

In terms of issues with the bag, I have three.  One is that one of my straps didn't have the leather properly and completely treated, so it had ripples and irregularities.  Not really worth fussing over, but noted.  Secondly, the back straps are initially QUITE long and you will have to either take them to a cobbler and have them trimmed or do it yourself.  I did it myself and so far no issues, but I'm keeping an eye on them.  Lastly, and not really a fault of the bag, but as a black canvas it does attract some light colored lint.  Lint roller generally does the trick but you have to be pretty consistent if you want a nice clean presentation.  On the other hand my black cat's fur doesn't show up at all, so win some, lose some.

I would definitely get this backpack again if given the choice.  I will update this review after a year or so and note whether or not it holds up.