I love this episode, though it's not perfect.

Martha has to save the Doctor and all of humanity by travelling across the world for a reason she does not disclose until the end. We get to see what the Toclofane really are and it's horrifying.

The Master of course gets defeated and Martha departs the TARDIS (good for her).

My main problems with this episode are generally around the "psychic network" that somehow makes the Doctor de-age and fly. This set of episodes do give it some time but it just feels like an unsatisfying way to win for me. This is true of a lot of episodes where they win because of the Doctor's arbitrary psychic abilities. Maybe if they had done something similar earlier on it wouldnt feel so out of nowhere