This plug's effect is indeed subtle, but it's there. My ears tell me the Amount knob dials in some slow-release compression, and there's a bit of high shelf EQ and/or harmonic excitement controlled by the "Detail" knob.
Try putting two or three of them in series and you should be able to hear what Neutrino does pretty easily.
Now the question is, why would you want to use this, when you can more readily control the sound with normal tools? I dunno about that.
Edit: inserting Neutrino on every track of a mix helped gel things together. I'd say the effect is similar to what you get from VCC or other console emulations, but with enough compression to solidify the mix a bit. Again, it's subtle. But I like it! Thanks, iZotope.
Cheers,
Eddie