Some of the Rustoleum paints are EXTREMELY hot chemically, they'll eat your next coat chemically if they haven't had time to cure properly... Their Painter's Touch line is a good example of that; They say you can recoat after 24 hours, but that paint will usually bubble and crack whatever you put down over it if you don't wait closer to 48 hours, even if you are using a perfectly compatible Rustoleum color over the top. It sucks to fix. Besides this, lots of brands (and of course paint types) will react with each other anyways. It's a PITA to do, but test-spraying sample pieces can save you a lot of work fixing.