Formal:
* Отлично (otlichno) - This is the most common and formal way to say "excellent". It's used in professional settings, written communication, and when addressing someone with respect.
Informal:
* Прекрасно (prekrasno) - This means "perfectly" or "wonderfully" and is a more informal way to express "excellent".
* Замечательно (zamechatel'no) - This means "remarkably" or "marvelously" and is another informal option.
* Супер (super) - This is a slang word for "excellent" and is commonly used by young people.
* Круто (kruto) - This means "cool" or "awesome" and is another slang word for "excellent".
Other options:
* Великолепно (velikolepno) - This means "magnificent" or "splendid" and is a more poetic way to say "excellent".
* Идеально (ideal'no) - This means "perfectly" or "ideally" and implies a high standard of excellence.
The best choice will depend on the specific situation. For example, you might use "отлично" in a formal report, "прекрасно" in a casual conversation, and "круто" with friends.