Decent to Very Good. Quality of the canvas, and arrangement/volume of storage compartments are excellent. I ride a motorcycle, so need a sturdy, waterproof bag. Haven't moved into the rainy season here in Seattle, we'll see. I only have 2 real gripes with the bag:
1- I wish it had a 3rd point of contact from the bottom righ hand side (when worn across shoulder) connecting up to the shoulder stap for a more positive control of the bag. (I had a "Buell" bag with this feature that was stolen and have yet to find an equivilent).
2- The left hand (when worn) strap loop (long rectangular plastic) keeps twisting so that instead of being flat with the sewn-in strap and the adjustable shoulder strap nice and smooth, it turns so the straps are scruntched up, and the strap lengthens just a bit.

With that said, I still think this is a pretty good product, one of the best out there, I just have very high standards for what I want in a long distance motorcycle messenger bag (I don't want to get a backpack, or use my saddle bags, because when I get to work this becomes my briefcase, so I want it to maintain a bit of a professional look)

I hope this helps somebody.