I modified an ST to an HSH configuration with these little buggers on neck and bridge position respectively (the middle one is still an EMG single coil for mixing)
The sound is really full and round yet still gives some "straty" quality to the overall tone. To me, it sounds still sharper than a genuine 335 Humbucker, foremost on the neck position, which was exactly what I wanted.
Using the included roll-back (which is sadly not optional, otherwise the entire configuration looses its solder-free quality) knob can still make it sound more "jazzy" (more like the one on the 335)
Only down side - with the solder free option, as mentioned before, only genuine EMG parts can be used. But since they are made to fit together perfectly anyway, that's not really a draw-back to me.
All in all I'm totally impressed.