I have put a pair of the GFS lipstick humbuckers on my epiphone les paul guitar. They have a very clear sound, even on humbucker mode.
If you want some gnarly mids you must look elsewhere. Its a very nice and useable sound, but you need a cranked booster in front of them definately.
I have never tried Duncans, but they must sound more middish, they use alnico 5 instead of alnico 2 that GFS use. There are also Artecs on ebay, they use Alnico 5 magnets.