I'll give you the same advice the folks at the Jayco factory gave me.... use the same type of wax/cleaner that you'd use on plastic boats or cars, i.e. Corvettes. They indicated there wasn't a brand they recommended; just use a high quality wax, etc. Myself I use Meguiar's and have had very good luck.
I'm sure others will chime in with other good products and ideas as "yes" this thread went around a few months ago. It's good that you asked though as I'm sure others on the forum would like to know the answer to this question and we all need to keep up with what's good.