When we purchased our 03 Dynasty in February of 07 it looked terrible. The 3M mask was yellowing and chipped up very badly. Exactly what it was designed to protect. I know the paint would have been damaged without it but it needed repainting either way.
I removed ours and repainted the entire front cap from the bottom up to mid-way up the windshield where I blended the clearcoat. What a PITA. Prepping and painting was the easy part.
I have not had any protection on the front of the coach for the past almost 7 years now and 40k+ miles and although it does have a few pretty nasty rock chips it is nothing like when we purchased it.
Mike.