Kermode? He's alright. He's done some good stuff on The Exorcist and The Devils. Some of his individual reviews are a bit perplexing in their conclusions e.g. Ghostbusters referenced above, and he can be a bit shouty at times. In the end he's a mainstream critic and tends to pander to that audience but I think his occasional in depth dips into cult films are usually worthwhile and insighful.
I think a lot of peoples perceptions of critics are usually down to to two things 1. delivery and 2. how they treat your personal favourites.
There are other reasons. I took a dislike to Barry Norman because he used to say that the most important part of making a film was a good script. No Barry! The most important part of film making is being able to capture an image - that's why its called film making you dunce! See, I still don't like him
