This is an exceptional Superman episode. This episode is head-and-shoulders above most episodes in the series; it definitely belongs in the coveted group of "top tier" episodes.
This review will not contain any spoilers, but this is an excellent episode due to writing. The plot immediately hooks you in, and it does so using an interesting narrative. There is a tight balance between action and story development, and there are several scenes that capture the Superman mythos nearly perfectly.
This episode maintains a strong quality right up to the last seconds. A must watch, even for someone who is not the biggest Superman fan.
This episode stands on its own as excellent television (animated or not).