I was looking through my SUPERMAN 400 issue (Oct 1984) that among a ton of other great work has a nice Superman pin-up page by Byrne.





It actually resembles the photo-collage work Grell was doing at the time in JON SABLE FREELANCE, that added to the realism of that series.
But more importantly, relative to the MAN OF STEEL, SUPERMAN and ACTION series Byrne was doing 2 years later, while still a nice pin-up page, it portrays a more slender Superman, and actually looks more like Reed Richards in a Superman costume. Byrne did FANTASTIC FOUR from 232-293 (1981-1986), and this pin-up was concurrent with his run on that series, out the same month as FF 271.

This was at the tail end of the period where Byrne was still doing good work. It was two years later, at the point Byrne began his SUPERMAN run in 1986 that I thought the quality of his work made a bad and sudden decline. Hit and miss after that, but the point where I largely lost interest in Byrne's work. I think his writing was still often good, but his art became a pale shadow of the greatness of his 1975-1982 period.