Por 15 vs. KBS Rust Seal

Has anyone heard of KBS Rust Seal and how does it compare to Por 15? The guy at the paint store said Por 15 is the same as it was in the beginning. No inprovments. KBS is from the same people that made the first Por 15, But went out on there own, made inprovements and started their own company. So it it any better? It is cheaper.