photo credit creative commons license Mark and Allegra
It seems that the question of the best superman actor is not a question to be taken lightly. In fact over the last 60 years there have been quite a few actors and each has his own merits.
Each time a new superman movie reaches the screen the discussion is reopened for example after superman returns reached the screens even those who were really appreciated Christopher Reeve’s superman had to appreciate the great work that Brandon Routh have done. See here for example
I decided to leave the decision open as the part keep changing and so does the demand from the best superman actor.