Well, they're not based on the same damn schematic as just about every budget and mid-level mic pre on the market is.
They're unique ... they have a unique sound ... kinda' gritty / crunchy, and when pushed they mildly distort in a nice way. They're based on API's. The "vintage" one actually sounds just like an API, and the other one sounds a little different but just as good. Like an API, they do something really cool in the midrange that's kinda' hard to explain ... but you can really hear it on a snare track.
They're not outlandishly expensive, and every last dollar is totally justified. The transformer alone is worth a good chunk of change. This isn't the kind of deal where you could just roll your own with a bunch of digikey parts for like 20 bucks.

And it's certainly not a deal where you could buy a cheaper version and get a similar sound. These are great value. You pay a little extra and you really get something with substance to it. I could go on for days about these things.
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