The dilemma of sequels, in comparison to the first in the series

Say if someone asks you your favorite film of the [random franchise] series. The first film is usually always the best. Even if you enjoy the sequels, they still owe too much to the original entry. Obviously, they wouldn't exist without the original, but the story of the sequels tends to always be very derivative of the original.

Do you concur with this, or can you think of examples to contradict it?

For example, I'm here thinking which Planet of the Apes is my favorite. Sure, I voted the first one the highest, but that's just respecting of its impact on film in general. I might very well prefer one of the sequels, but damnit... I'm just not sure.