I can't speak to Jeff's personality, having heard him speak only once at a Bass Day event here in New York. But I have frequently read his former column in
Bass Player magazine, plus occasional published interviews with Jeff. And all things considered, I find very little with which I could disagree.
The guy's criticisms of musical crutches like tabulature, those goofy "You Too Can Develop Perfect Pitch" courses advertised in the music magazines, and other assorted forms of instructional snake oil are right on the mark.
Music is music, and a well-rounded musician will be able to read, transcribe and understand theory, as well as be able to improvise, learn/play by ear, know how to create a part that is appropriate to a particular genre, and yes, groove - regardless of which instrument(s) he plays. Again, leaving aside the issue of whether or not one likes him personally, Jeff is pretty much telling it like it is.
One may call that "old school". I call it the truth...
MM