Re: Thoughts on G&L MFD pickups....
G&L pickups are generally as good or better than any Fender pickups, and whether or not you change them, is a matter of taste. The Z-3 pickups are great, although not for everyone. I really love the sound of the soapbars in the G&L Asat Specials.
I'm not sure what's in the S-500, but I did like the sound of the pups in the George Fullerton model. G&L pickups may not be as good as the best Duncans, but they sure aren't trash.