I don’t know anything about the developers, except they seem to know what they are doing when it comes to making real, physical amps. They design and produce custom ones, and then model them in software as well. Or maybe it’s the other way around in their development process. Either way, this freebie will surprise you!
For a look at how the Pultec attenuation/boost trick works, see the UAD Pultec post. Yes, it’s really cool and esoteric, and somewhat mystical.
And you can compare it to the Waves version, IK Multimedia version, Tube-Tech’s modern version. Mystical is a good sales tool, no doubt.
Read some good reviews for some real amps here: Best Guitar Amps for Metal