This is one of my favorite things ever. I use it for everything! Trips to moab, trips abroad, trips to my Mom's... I always throw it in the back of my truck. It has been rained on and snowed on. Because the lid covers the zipper, you have to make an effort to get things on the inside wet. The backpack straps work great - but if you're going to fill it up and carry it like a backpack, I wouldn't get anything bigger than the large... I've had the blue for over a year and it is mega sturdy - still looks new.