When ordering RG6 Connectors on line, they list yellow cad & tin plated. Both are about the same price. What is the difference?

Nothing. I've never seen anyplace that would give you that choice, why bother.

The finish is a manufacturer's preference that applies to the entire line. For instance all Gilbert connectors always were yellow cad while LRC are tin plate. Good way to tell manufacturers apart but that's about it.

-Hal