Which is the best ceramic coating?
The main differences between brands of ceramic coating tend to be in ease of application, supply, customer service, warranty etc. The difference between actual products is minimal, which is understandable as the product is a microscopic layer of ceramic. Either the product can do this, or it can't.
The more expensive products generally last longer because they are more durable, this also means they are tougher and may be more scratch resistant. Most brands offer a range of products, and they tend to be roughly equivalent to other brands.