I wish I owned one of these ten or even twenty years ago. This bag is as close to perfect as I've encountered. Construction is solid, the canvas is reasonably durable. I waterproofed it with a spray-on product from a local camping/outdoorsman's shop.
The best thing about this bag, though, is the size. Not too big, not too small. It is perfect for my Nikon D1x (F5-size) with lens, an additional lens or two, both spare batteries, SB-28DX flash, my Linux subnotebook, several compact flash cards, and lens cleaning kit.
With some cramming, I have been able to squeeze an F100 camera body in as a film backup, but this is not a comfortable fit for the bag. I have a larger bag for when I need more gear, though.
This bag is perfect for light-to-medium travel. In other words, most of the time.
Cheers!