Ebert gets very sarcastic with people who disagree with him. Siskel took it all in stride. He could stand up to Ebert. And could throw a few zingers at Ebert when the fat guy made a terrible pick of his own.
Siskel was older, had gone to a more prestigious college (Gov. George Pataki was a pal), and worked for Chicago's biggest paper. His self-image didn't depend on what Ebert or other film geeks thought of him. He made some bad calls, but his and Ebert's balanced out.
The old show worked because Ebert spoke up for his avant-garde favorites and Siskel represented more middle of the road tastes. Today, Ebert tries to occupy both seats, and it doesn't work.
Ebert's choosing a junior writer at his own paper as Siskel's replacement was a major mistake. He doesn't have anyone to play off him or to stand up to him any more. It weakened the show, and indicated just how insecure Ebert really is.
Agreed.