If we're only talking about art, I'd go with Perez, but once you say creator, then Byrne's co-plotting with the X-Men, plus the important writing he's done with the Fantastic Four and Superman come into play, and I think I'm too confused to vote. If I'm being honest, it's probably Byrne do to the "extra credit" for his writing, but I just don't think I can vote against my favorite artist George Perez.

Even if, at their best, they were equals in art (which they are not), Perez is more consistent and (far more importantly) he works well with writers and editors.

When I posted best artist I meant top creator all around. They both co-plotted And wrote as well as, penciled.

If writing is in the equation, then I think we have to talk about this:

It's impossible to be objective in this, since about the only measure you can use that is remotely objective is sales figures. In that, Byrne probably has the edge, based on X-Men and Superman. I have no idea how well FF was selling, though I believe the Byrne issues were the highest sales the series had had in a long time. Avengers is harder to say. Perez worked on it during the Korvac Saga, which sold a lot of issues, while Byrne had the Wundagore storyline. Superman proved to be a really big deal and Byrne is all over that. Perez did great work; but didn't really reach superstar sales status until New Teen Titans. That was followed by Crisis, which did huge numbers.

I prefer Byrne's work up through Superman; and, then, after, I find him very hit and miss, both in writing and art. Perez is consistent, though I kind of thought he was getting a bit self-indulgent in some of his projects, trying to cram in things for the sake of seeing if he could do it, rather than in service to the story. Perez was better on team books, from my perspective, though it's still a close call. Byrne did individuals better, in my opinion, and worked better with a smaller cast. Really, their careers are very similar for a long time. Both did a lot of team-up stories, team books, secondary titles and features, before building their names on a team book that was more of a family. Byrne was the superstar earlier, with X-Men, though Perez didn't lag that far behind, with New Teen Titans. With Byrne peaking earlier, I also think he burnt out sooner, which is part of why Perez is more consistent.

I would say going into the 80s it was Byrne; but, coming out of it was Perez. By the mid-90s, though, both were in a lower profile, picking and choosing their assignments, writing more for others.

In the 80s, when MArvle and DC wanted to create the biggest comic project ever using their flagship properties in the JLA/Avengers cross-over, it was Perez they turned to, not Byrne to do the job because that's what fans at the time wanted to see and who creators and editors wanted to work with. Now the project didn't happen because Shooter couldn't play nice and it took almost 20 years and a couple of regime changes for a JLA/Avengers to happen with Perez still attached to it, and the biggest impetus behind it was that people wanted to see what Perez could do with it.

By the late 90s when Marvel desperately needed to revitalize their main line of books after Heroes Reborn they first went and got Perez to do Avengers and found a writer later to work with him (it was supposed to be Englehart but that didn't work out and it became Busiek). they didn't turn to Byrne because his attempts to revitalize Marvel characters (like Spider-Man) had been disastrous.

In the 70s and 80s, the two essentially went tit for tat with their accomplishments and renown, with a slight edge to Byrne, but by the time you move into the late 80s and 90s, Byrne's rep and successes were already falling off while Perez's was still growing and he was still getting prestigious projects because he was still delivering and Byrne was disappointing. It's a close race, but it we take their entire ouevre from the 70s to the 90s as the op outlines, then I think the edge goes to Perez.

-M

Wow, tough tough question.

My first instinct would be for Bryne. Growing up, his output is nigh synonymous with the 80s, from UXM to FF to Avengers to Alpha Flight (!). Later his work on the Legends mini-series followed by his relaunch of Superman was incredible.  He has one of the most distinctive art styles in the history of the medium which is instantly recognizable and enjoyable.

But if we're discussing over the long haul, then I have to go with Perez. Along with various assignments for both companies over the years, I think his work on NTT carries more depth and quality overall in terms of characterization and story, his 90s run on Avengers restored some of classic feel of the team and characters, and finally he came fully into his own as a writer handling the relaunch of Wonder Woman which still rates as one of the best, if not THE best, interpretations of the character.

More simply, art-wise, both are classic and unique and genre-defining and it's really hard to favor one over the other. As for writing, I think overall Perez is better and more consistent.