Well if it helps, I got acquainted with that art in 2010 amidst everything else that was. So their art did not appear to break free from the crowd. It just looked like standard proportions to me. Well done for sure, but nothing I could pick from a line up if they drew a scene I was unfamiliar with. Unlike Miller, Simonson, or the aforementioned Bolland. Not saying Miller is a better artist, he is not, but his style is more recognizable to me.
Also I thought Perez was picked for Superman to indicate to readers that the title was returning to a more classic and familiar feeling, that alone tells me that his art is not that distinctive when compared to other artists.
Maybe it comes down to you had to be there in 80s to understand how truly unique Byrne and Perez were. I can't imagine looking at their work and not immediately recognizing their distinctive styles. To each his own indeed