I just started replaying 5 after beating PW and recently MGSDelta and I have to say it aged like shit.
The graphics look really bad, at the time I thought they were "ok" but man did the open world aspects of the game really put it in the deep end of unimpressive visuals, aside from the nice cutscenes that is.
Hell I'd argue Ground Zeroes looked better but that was because the game was entirely condensed into one area.