His work on X-Men was my first big exposure to modern comics. He's very talented, but dated. His style and pacing are great for comics from the early 80s, even into the 90s, but what was top O the line 20 years ago doesn't cut it today. He's very cartoony, when today folks seem to favor a more realistic/photo level of work (overall, there are always exceptions).
But a student of comics and comic art could do a lot worse than to study Byrne's works over the years. He's got some of the most solid mechanics, and a heavy Kirby influence to his art, while his writing style...hit and miss at times...does the job better than some, especially as his words relate to the art. He does "get" that comics are a two-medium forum, and knows how to blend image and word to tell a story.
I just don't think he's got any stories left in him that people care to read these days.
And of course he comes off as an abrasive prick a lot of the times, which in a small community like comics doesn't help much.
But he was one of the top names that carried comics from the 70s through the 90s, and there aren't many that you can say that about.