Just picked up a Wide (model 117) Weatherguard for myself... I had one from Home Depot on another truck and it leaked a little, and the latches and locks got cranky after a couple years. A construction superintendant I know says their Weatherguard boxes last them two trucks (meaning about 10 years of construction life).
The weatherguard on my company's truck is 3 years old and still works just like the new one I bought.
Plus - in case you didn't know, theres a handy sliding upper shelf to hold odds and ends like screwdrivers, Pliers, utility knives etc.