I've had my bag for a little over 18 months now. In that time it's done everything from cross town deliveries to being used as my main luggage when flying (just the right size for carry on baggage with a long weekends worth of clothes).
I must have got lucky because mine came with a cross strap to hold everything steady and the bag itself has been faultless. It still looks new with only a small bit of surface abrasion from getting knocked off my bike once.
It's as weatherproof as you'll need, holds everything securely, will last you a lifetime and looks the mutts. Buy this bag.
If looking for a courier bag i would recomend this one, it is simply the best, fully water proof (as proved through a scottish winter), big enough for everything and takes everything that i can throw at it.
