Asking what the best wax is, is like asking what is the best oil. Everyone will have a different opinion. Plus there are different type of wax's like compounds, cleaners, sealers and carnubas. If there was one that was clearly the best, all of the other wax companies would be out of business.
2015 Ram 3500 Regular Cab DRW CTD Asian trans 410 rear
I use a product called Voom because it's easy to use and the dealer at the place I bought a travel trailer once said it is what they use on all of their used RV inventory. I've read good things about Rejex though and may give that a try.