Systems like the slate VRM have some smart modelling software and excellent marketing in them. The only problem is that for anything close to an *authentic* sound, it is very reliant on having an uncoloured signal on the way in. If the acoustics of your room are colouring the sound, this will overwhelm any subtleties introduced by the mic modelling.
There is an ongoing question as to the true quality of the microphone and preamp as well. Again, for the modelling to get you close to the originals, it is vital that the mic & preamp impart no sonic signature of their own. I've read a number of reviews which question how much the system really gets to sounding like the classics.
(For real pessimism, tech-head opinions and some input from slate himself, see here:
https://groupdiy.com/index.php?topic=54971.0)
My personal opinion is that if you look beyond the flashy marketing and proclamations of having all these classic mics at your fingertips, you actually have an interesting collection of different tonal controls and a slightly different way of approaching recording/mixing.
Its certainly very interesting & useful and they have a history of good plugins (I am a fan of the virtual console and the mastering plugin), but I dont think it is breaking new ground. At the end of the day it is a (potentially/possibly?) good microphone and preamp bundled with some interesting tonal & distortion plugins.
I would love to see a company actually break new ground with microphone hardware and finding a real way to consolidate using transformers, tubes etc to create the distortion & tonal artifacts that people love so much with a modern 'internet of things' connectivity & usability.