As you see in the responses so far, I think it is really a matter of what kind of food you prefer, rather than which restaurant is "better." We love Le Cellier, and were disappointed that we could not get near it in December because of all the Candlelight Processional Dinner Plans. We remember when Le Cellier used to be the best kept secret in Disney and we've always have wonderful meals there.
On our May trip, however, we are going to be lucky. We got Le Cellier, and because we've heard so may rave reviews about Coral Reef, we also have an ADR there. We also have Teppenyaki, another restaurant we've never tried but have heard good things about.