I guess I'm one of the lucky ones.
I have Diamond Shield on my motorhome and after 10 years it still looks like new. I do remove the bugs by hand (no power washer) as soon as possible, and apply a coat of wax a few times a year as recommended in Diamond Shields instructions.
I haven't tried the 303 Protectant yet.
Current:2008 Triple E Commander 3202FB V10, F53, CHF, Safe-T-Plus, 5Star tune, 2008 Edge Limited AWD Toad, Ready Brute Elite towbar, Demco baseplate
Past: 8 RV's over 32 years.