Tight and thick lows, growling mids, shimmering highs with immaculate clean tones. They're in your face with the volume at 10, but if you roll the volume off a notch or two they cool down a bit without losing their punch. The full range of volume and tones are just luminous through and through.
I have installed the set into several guitars and they have sounded especially great in mahogany bodies, but an Epiphone Explorer with the mysterious "korina" wood sounded terrible with these in (bringing out the thinness, dullness and plastic-like sterility of that particularly guitar), reminding me that electric guitars are indeed semi-acoustic instruments. So after a year of using the Black Winter set in several different guitars, I find the drawback is that these are so neutrally EQ'ed that they might bright out the weaknesses of your flawed guitars. In a Gibson Les Paul and an Epiphone SG these sound great without any such problems and without the woof or fizz in comparable Seymour Duncan models like the Nazgul, Invader, Dimebucker, and so on.
The Black Winter set are in my view one of the, if not the, best high-output passive humbucker sets out there: rapacious, melodious, and smooth as glass if you want. With these in a Les Paul it feels like I finally have a guitar that could cover most styles I play, and if I set the selector between Rhythm and Treble, roll my knobs to their sweet spots, then I can satisfactorily substitute my Stratocaster's neck pickup. So for me these are keepers: with the same guitar I can play exacting, heavy music while rolling back the knobs to get the lush clean tones I want for playing softer, more tonally varied styles that I spend most of my time on at home.