Totally agreed. That was the period that most made Metropolis feel like a strong setting, a real lived-in city. In my opinion, every single supporting Superman character is at their absolute pinnacle during the Triangle Era, except for Jimmy Olsen, Lex Luthor, and maybe Cat Grant, because I think I actually prefer her under Wolfman.
And, er, Superman and Clark himself, who get better as the post-Crisis era goes on, but whom I probably prefer in a good few other eras.