I have a Lone Peak barbag that I've used for thousands of miles. I don't like it. Mainly because you have to put a cover on when it's raining. I was once in a tremendous downpour in IL and the cover filled with water. The bag and its contents (including a cellphone) couldn't have got wetter if I'd plonked it in a bowl of water for a couple of hours. Also when you put the cover on you can't read the map in the handy map pocket. You have to loosen the cover and push it back to see the map, quite tricky on the move. The guy who sold me the bag said the thing to do was to cut a hole in the bottom of the cover to prevent water build up!
When I can afford it I'm going to spring for a waterproof Ortlieb bag like my wife has. Mind you they ain't perfect, for some reason Ortlieb provide this lock feature that's as much use as a chocolate teapot.