John co-taught my final two weeks at Clarion with Jim Kelly in :::cough, cough::: 1996, so I'm partial, but I think he's a brilliant writer. But don't take my word for it. ABC dramatized one of his stories in "Masters of Science Fiction" a year or so back and he's traveled all over as an honored guest.
Marshall's interviews always draw something special out about process or the field. All you have to do is go back and read a few: Mike Allen, Jim Kelly, Greg Frost, all of them, in fact. So drop in, put your feet up. The drinks and munchies are free and you're always welcome in the clubhouse. Until we kick you out.