The weight of the evidence is heavily in favor of the antihedonist reading of the Protagoras. It is thoroughly compatible with the text of the Protagoras; it is intelligible in the light of a plausible account of Socrates' aims; and it can meet objections to it, whereas the prohedonist account creates more problems than it solves.
Zeyl, Donald J., "Socrates and Hedonism: Protagoras 351b-358d" (1980). The Society for Ancient Greek Philosophy Newsletter. 119.