Les Claypool is quite brilliant, I find though that when listening to Primus, you have to adjust your focus and attention on the music to the bass (because honestly what his face playing the guitar is honestly just god-awful).
IMO, in Primus the role of the Bass and the Guitar have been switched, the Bass is the true focus of the song, the guitar is there to support and add depth of sound (at the high end of the range rather than the low). I thought Primus was absolute crap until I figured that one out