Lots of fine harmonica players such as Alan Wilson, Don Brooks, Jimmie Fadden, James Cotton, DeFord Bailey, Norton Buffalo, Mickey Rafael, Doc Watson, Charlie Musselwhite, even Pigpen had his moments. Who is great (or greatest) is a matter of opinion. Style is what counts, as well as how much the player adds to a song.

Paul Butterfield deserves a great deal of appreciation for starting a fine band that did a lot of great shows and made a plot of people happy. Some harp players were better technicians, some not as good. That ain't the only thing that goes into being a good musician.