As much as I like Clive Reville, to me it has a lot of hills and valleys. This might be a ridiculous complaint, but one of mine is the title, since it's nearly the only title of the whole original series that doesn't try to be colorful at all, so it sticks out for that reason.
I do like things like the comical pub scene with the limericks (I'm pretty sure it's the first place I ever heard that "What a wonderful bird is the pelican" one).
Some people have said they really prefer Jeanette Nolan in THE CONSPIRATORS to Jeanette Nolan as uptight Mrs. Peck in DOUBLE SHOCK, and that's understandable, but to me it's the other way around.