I have bought and installed GFS pickups in 5 of my guitars. What does that tell you?
I started out buying a Crunchy PAF for the neck position of my Jackson Rhoads Custom. It sounded so great, and complimented the Seymour Duncan SH13 in the bridge position, that I bought another one for the neck position of my Xaviere XV500. It has a Duncan Custom in the bridge, and they go really well together. Finally I decided it was time to try putting a matching neck/bridge set in something. I had just picked up a NOS Aria Pro Custom X from Japan, and the stock pickups were kinda weak sounding, so I ordered a set of Crunchy PAFs for it. The bridge pickup is even more killer than the neck. It actually has a similar output and sound to a Duncan Custom. I liked them so much, I put another matching set in another guitar. I also used a couple of overwound GFS single coils in a Strat I built with a Duncan Custom in the bridge.
Someone also mentioned the Mighty Mite Motherbuckers. I have a set of those in another guitar, and they also sound fantastic.