Well, after spending a week with the MuRF it now has a permanent place on my board. However, I must say that across my 4 electric guitars (Anderson Hollow T, Grosh Classic, PRS Archtop II and Gibson '58 LP) the Anderson and the Grosh sound the best through the MuRF.
Net, at least for my taste, the less "hot" PUPs seem to react better with the MuRF.