Siskel wasn’t really a film buff. He never went to film festivals and never wrote about film outside of his newspaper reviews. If he ever read book on movies it would be news to me. Ebert was a real cinephile and passionate about the artform.
I always liked Ebert because he was the first critic I remember, and still one of the few out there, able to publicly enjoy both high art movies and popcorn silliness. His love of Russ Meyer kept him grounded in everyman films, movies other critics’ egos wouldn’t let them admit enjoying Ebert would be right out front saying “yeah it’s not high art, but you’re going to have fun”. Which is why I always found him to be the better of the two.
Since I have never put any stock into critiques of movies, by Eggbert, or anyone else, I really do not care if Eggbert was a cinephile. He was a liberal jack@ss, and that was enough for me to dislike him.