The S-Class sedan outsells the CL-Class roughly 10 to 1, but that doesn't make the big coupe a failure. Even though two-doors aren't as popular here as they are in some foreign markets, Mercedes says the U.S. is the CL's biggest market. Exclusivity is a major consideration among luxury-car buyers, and the rarity of large luxury coupes seems to be serving the CL-Class — and its buyers — well.