• Nazgul is tight with a thumpy bottom end and a unique high-mid structure that really cuts. It has a "mean" sound to it in a mix with lots of clarity. Unfortunately, it can be picky like a JB (reasonably balanced in some guitars, overtly honky in others) and is a little over-the-top for some styles. It doesn't play nice with every setup, but when it clicks, it's a monster!
• The Omega is tight and articulate with a muscular midrange focus and brighter overall response that works very well to balance out darker guitars. There really isn't another SD voiced quite like it. It's not as "hot" as you'd expect and, on its own, it lacks a bit of body down low, but that's also why it's one of the best options for "busy mixes" and multi-guitar bands.
• The Alt 8 has a slight upper-mids emphasis, but the top end doesn't get overly piercing or thin. That said, it can come off a bit "dry" sounding in some guitars. It has some low-mids weight to it, but the bottom end isn't quite as tight as some of the others mentioned here, though I wouldn't go so far as to call it "loose" either.
• The Custom, of course, is pretty much good at everything. Hot, punchy, and lively, but controllable. A moderate low end with a bit of bounce that tightens up nicely under gain, a very balanced midrange, and a top end that is plenty clear, but doesn't over-emphasize a particular frequency. A true "jack of all trades" pickup that should be the starting point for anyone getting into SD's higher-output models.
• The Dimebucker is a closet slayer that doesn't get enough love these days. Like the "Bill Lawrence" design it's modeled after, the Dimebucker somehow harnesses qualities of both a Distortion and an overwound Tele bridge pickup to create something that combines classic pickup character with modern clarity and articulation. Very punchy with screaming harmonics and a touch of twang when backed off or split.
With all that said, the BW combines the tightness and clarity of the Omega/Nazgul with the thickness of the Distortion and the balanced, "do it all" voicing of the Custom. EVH? Check. Pantera? Check. Periphery? Check. Dokken? Check.
The BW has growl and fullness with plenty of bite and an extra dose of aggression when you dig in. Plus, it sounds incredible split. It's a modern classic whose branding as a "black metal" model does it a bit of a disservice, IMO.
If SD pared back their "high-output" offerings to just the Custom, JB, Black Winter set, and the Alpha/Omega, 99.9% of "high output" players would have their needs met.