The biggest problem I can think of with Spartans is the fuel tank. They hold something like 495 litres, and unless kept full condensation will be an issue. They are also filled through a hole in the roof and sand and dirt can easily be washed down inside. Despite a lot of cleaning, we could never get ours fully clean and didn't have the cash to fill it up, so we run from a jerry can. Eventually we plan to lift the tank out and fit a smaller plastic tank inside it, some owners ditch it completely to make more space inside.
Chris