I have a feeling tolworthy is preparing a multi-page essay to answer this question
But since I'm here first, I'll say that as a kid, I loved the Byrne run. Byrne was writing and drawing FF when I began reading the title (#280, no comments please) and when he left, the life was sucked out of the book for me. At the time it was coming out, his FF run was a big deal and considered by many to be the high point for the FF since Kirby left.
However, I don't think history has been so kind to the Byrne FF run. In retrospect, a lot of what Byrne did hasn't been looked at kindly because he was aggressively attempting in many ways to return the FF to the Lee/Kirby era at the expense of dumping all the growth that had occurred in the intervening 15 years. For him, the Lee/Kirby FF was the only real FF. His FF run is one of the first instances of this kind of creator retro-continuity, where the creator is specifically trying to recreate the "ideal" era of his own reading days. It's something Byrne has been guilty of throughout his career, but beginning with the FF; his incredibly damaging and retrograde run on Avengers West Coast was just an extension of what he started in FF. Byrne basically had specific ideas of what worked and didn't from the Lee/Kirby era, and what he thought worked he returned to that status quo and what he didn't like, he pulled down with a jackhammer to "fix" things to the way he thought they should have been.
In short, whereas his X-Men run was both tempered and enhanced by the fact that he and Claremont were clashing on ideas and thereby creating checks and balances, with FF his ego was able to run amok in a way that seemed fun at the time but which is not nearly so fun now.
He wrote and drew some really excellent stuff for FF, but as a whole, it's not a run I feel like revisiting at any point because it represents the beginning of a way of thinking that has in my opinion has stunted and damaged the industry as a whole: nostalgia driven revisionism. See: Brand New Day.
He does get props for having Sue change her name to the Invisible Woman from the Invisible Girl after 25 years, though.
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