According to the test done by wetshine, coatings don't do well in the rainy Malaysian weather because they are more prone to waterspotting compared to waxes/sealants. The conclusion is in the comments as the tester did not want to continue with the blog entry for coatings.
Waxes/sealants don't hold well/last long on coated surfaces so owners must wash/more often to get the waterspotting under control. Or just let leave the spots there and let the coating act as a sacrificial layer until it wears off.

Edit- add the link:
https://wetshinedotnet.wordpress.com/2011/0...st-application/

This post has been edited by derail: Feb 25 2015, 11:31 AM

Coating retain more waterspots and polishing more often to get rid of the waterspots degrade the expensive coating. So be prepared to live with more waterspots if you want the coating to last. Waxes and other lsp don't last as long (cannot stick) either on coatings so thats another drawback for detailers.

Some lsp's under the same brand might do better as a topper on a coating, which could be a way to get customers to visit the shop more often if the lsp is not sold in retail outlets.