best episode of his?

My vote is TIME WARRIOR. The show went through some major transformations over his tenure - first with going from black and white to color in his first episode, and then gradually over the course of his 4 years going from silly pulp scifi (monster of the week attack) toward the more gothic pulp horror-scifi of the Tim Baker era. The best of these in-between episodes I think came later in his tenure.

TIME WARRIOR I love for many reasons, namely the acting and interesting plot. The invention of the Sontarans is one of the most inspired moments in all of Doctor Who, and I find the realization of them in the first couple episodes a brilliant balance of humor and terror. Lynx and Styr, as excellently performed by Kevin Lindsay, were perfect foes for the Doctor as they took themselves completely seriously and were pretty cunning and clever. At the same time they had some large flaws in their logic which The Doctor would amusingly exploit. Unlike Daleks and Cybermen, Sontarans seemed a lot more rational and thoughtful about what they did, and not so much "evil" as a mix of coldly "scientific" and "militaristic".

I love the uneasy alliance between an all-business Sontaran and a chaotic medieval warlord too. I wish the show had more situations like this.