I can comment on three of the restaurants you mentioned.
Nine Dragons is probably the worst place we have ever tried at Disney. Perhaps coming from the New York area has me spoiled, but I can find exponentially better Chinese food on a random street corner for literally half the price. Not to say that the fare at Nine Dragons is awful, but it's absolutely not worth wasting a coveted Disney meal unless even mediocre Chinese is unavailable in your hometown.
Les Chefs de France is solid. Nothing special, but definitely worth trying. The atmosphere absolutely enhances the experience. Take a look around and try to imagine eating at a cute street cafe in Paris. I like the lobster bisque, but the rest of the food was just decent. The service and environment are wonderful, but the food doesn't quite meet expectations.
Hollywood & Vine is perhaps the most standard, nondescript restaurant on property. It's a basic buffet without few defining qualities. We had dinner there several years ago as part of the Fantasmic! Dinner Package, and I can barely remember the meal. I know we left relatively satisfied and without complaint, but I wouldn't necessarily go back, especially considering the other options at Disney's Hollywood Studios.