I use the spray Meguires Ultimate Synthetic on the Mercedes. It stays inside most of the time though.
It doesn't stay on as well as the paste waxes but it doesn't smear when hot etc either.
About time for clay baring and good polishing by hand only and another wash and a good Meguires synthetic waxing. I also wax the windows with the spray synthetic.
The Rejex is good stuff but not as easy to put on and not a glassy.
Meguires is not the only good car care but it does until I find something better.
The spray on protective film, I heard about on RV net is what I want to put on the front of the coach and the Mercedes when I can get around to it. I hate bugs and grit.
I have someone that details and does a super job, since I can't and see what he thinks about the spray on protective film.