"What makes you happy as a guitar player?"
The answer to that question is the sum of a lot of aspects. Some are small, some are significant.
Some are relevant for ALL guitar players, while other seem to bother only you.
Most of these aspects are highly subjective; still I'll try to describe my findings in an objective way ... about this particular guitar pickup. The EVH Frankenstein.
------
Musical style?
OK, I play down-tuned Metal on a baritone guitar (Solar 29 inch). But I'm also raised with (and a huge fan of) Stevie-Ray Vaughan & Eddie van Halen. So I guess I want a combination of an smooth, earthly, organic, growling 80's rock sound, together with huge amounts of gain & tight palm muting.
------
Specs?
There aren't any. Unofficial statements mention an "aged Alnico 2 magnet" with an "overwound (14.4K) 42AWG coil". OK, at least that something.
------
What are my references?
The Solar guitar comes with "Duncan Solar Alnico 5" pickups; they sound pretty darn good.
I tried Bare Knuckle Aftermaths; perfect for Metal, very precise and aggressive.
I bought and tried Seymour Duncan APH-1; the other side of the spectrum. A weak Alnico-2 magnet, very soft and clear, almost a single coil. Not particularly suitable for high gain. But what I DID like about these pickups, is the "feel". Ooops! Sorry! Way too subjective. Let my try to explain that.
------
Why does the APH-1 make me happy?
1) I like it when the sound changes when I "dig in in the strings". In other words: hit the strings different or harder.
It only has to do something with dynamics on the input side (being: me). The output of the Aftermath for example, has more dynamic range than the APH-1. It's just that the tone changes when I change my way of playing; and I like that.
2) I like it when I hear a clear attack, in all of those high-gain walls of guitar. Both for soloing and riffing.
3) I like a nice "Hooomph" when palm muting. Who doesn't? ;-)
------
OK, is there anything else to wish for?
Yes, there is. Because the APH-1 is so bright, the overdriven sound is too gnarly.
What makes an high gain amp roar? Mid-range.
And that's where the EVH Frankenstein comes in.
It has what I love about the APH-1, but then with a clear mid-range focus. The frequency response is what you need for hard rock or metal. The overdrive now roars like a lion.
------
Is this a pickup for everyone?
Probably not. If you want ultimate Metal precision, go for something Ceramic like the Aftermath.
If you're a blues player, this pickup is too mid-focused. Pick something more open and clean like a APH-1.
If you're like me, that likes the best of both worlds (old-school brown sound & modern metal) ... this EVH might become your "go to" pickup.
And if you're after the Eddie sound (either the old-school brown sound or the newer 5150 sound) ... you just found your Holy Grail.
You can't go wrong with this pickup. I absolutely love it.