What is the antonym for unsatisfactory?

The antonym for "unsatisfactory" depends on the context, but here are a few options:

General:

* Satisfactory

* Acceptable

* Adequate

* Good

* Excellent

* Superb

More specific:

* Pleasing (if it's about something aesthetically pleasing)

* Successful (if it's about achieving a goal)

* Effective (if it's about a process or method)

* Beneficial (if it's about something positive)

Formal:

* Commendable

* Exemplary

* Outstanding

The best antonym will depend on the specific situation and what you're trying to convey.