"top" boxes (like the one OP pictured) I don't know if I've ever seen one mounted in the bed of a truck. I'd love to have the larger box in my truck but didn't get one because my thinking is that lids are typically not stepped and part of the lid lip faces forward.
The "chest" style ones (standard job box) you do see all the time. had a Ridgid one for maybe a decade and upgraded to a larger Knaack nearly that long ago again Zero water issues. Its a 4830 so my back window is useless but at 48" wide I can easily stack longer material like EMT on one side of the cab and a 6' ladder on the other side.
Here is an older picture of the dividers I made for mine. All friction fit with nesting dados. missing from the picture are 2 full length sliding trays (one on top of the other that can slide past each other), false bottom for material I need but hardly ever use and nesting material trays.
