Formal:
* Excellent: This is the most common and direct translation.
* Très bien: This means "very good" and is a suitable alternative.
* Parfaitement: This means "perfectly" and is often used in more formal contexts.
* Extraordinaire: This means "extraordinary" and emphasizes exceptional quality.
Informal:
* Génial: This means "great" and is a very common and informal way to say "excellent."
* Superbe: This means "superb" and is a more formal option for informal situations.
* Top: This is a slang term that means "excellent" or "awesome."
The best choice will depend on the specific situation and the level of formality.