You'll get the most durability out of a synthetic sealant. Online vendors like autogeek carry some great products not available in your chain stores that are much better. For locally available products, Collinite is an excellent product with good durability. For someone like me who details as a hobby and enjoys the extra time and effort it takes to make things shine like a jewel, I love products by Blackfire. The single step polish/ sealant is my first choice for a bigger project like an rv. Economical? Probably not, but I can really appreciate the difference in a high end product when I'm done. Klasse ALl in One is another good one step product.