Feyerabend: heathen, yes, anti-science, no, at least not until Farewell to Reason (but really what he opposed was the employment or diversion of science to authoritarian, anti-democratic ends: invoking “expertise” so as to shut off debate and exclude “laypeople” from decision-making). Certainly not a nut-job; he disliked academic stuffiness and professorial anxieties about respectability and stuck many a pin in many an inflated ego (read “New Clothes from the Emperor’s Bargain Basement” to see him take apart Larry Laudan).
I once read all of the reviews of Against Method I could find. Very few of them took the trouble to understand his arguments. They mostly got stuck at his announced “anarchism” and the slogan “anything goes”, and thereupon stopped reading. Feyerabend quite understandably became angry at his treatment by the reviewers. Admittedly he was given to boxing the ears of those he thought were deliberately obtuse, but he also with some care reiterated the points he thought they had missed.
Professional philosophy has since his heyday gotten even more stuffy and respectable. I can’t think of a single figure who even begins to approach Feyerabend (or crazy old Popper, for that matter, the High Priest of Objectivity from whom F. and several other well-known philosophers of science were apostates) in their willingness to question everything rather than sticking safely to some well-trodden terrain of “problems” and “solutions”.