I've been using 2 of the non-Brute Rubbermade 14 gallon containers for a couple of years. One for a tool box and the other for oil, ATF, and other consumables.
Work very well inside the vehicle, take lots of abuse and easy to clean up the spilled grease and oil. They do scratch and will discolor from dirt and grime, but all-in-all a cheap effective way to carry greasy stuff.
Not waterproof so putting up on a roof rack is not advisable. I thought about fitting them with a rubber gasket, but never got around to trying it.