Does anyone know the advantages and disadvantages (besides price) of ceramic rims?

Somewhere I heard about another type of coating that is supposed to be even better than ceramic. Does anyone know anything about it?

Also, someone told me that DT makes better ceramic rims than Mavic. Are they better? Are there other companies that make good quality ceramic rims?

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Side note: Is it possible to coat rims oneself? Where could I find out how to do this? (My main interest is in minimizing wear on the rims (from brake pads).)

Or, are there companies that do this sort of thing? -- could I bring in some rims and have them coated (either a ceramic or some other coating)?