I had to fight my metal-over-plastic instinct when it came to jerrycans. I've seen some metal ones rust internally and affect the stored liquid. Plastic ones ar

I had to fight my metal-over-plastic instinct when it came to jerrycans. I've seen some metal ones rust internally and affect the stored liquid. Plastic ones are color coded which is another boon. They're lighter, and you can get them smaller than 20L. Edit: some of the plastic designs get a bit excited with the molding and have fancy shapes. They look like they stack with other cans of the same brand. There are probably other benefits to their nice designs. But otherwise keep them rectangular and close to the original shape if carrying many/using them in frames designed for jerrycans (e.g. external storage on a 4WD).