I work with a Producer who uses the Slate with the modelling software.
It basically works, and gives you some change of character in a fast way.
It is ok... again... how can I say this...
If you are someone who really can live with one mic because you are tracking instrumentation elsewhere and/or building up tracks virtually rather than tracking, then this can be a great tool.
It gives you a decent sounding microphone where you can bring in any client, grab your one mic, record the vocal without much forethought of choice and afterwards go through your mic simulations and pick out the best fit you have.
I sounds somewhat reasonably close, and you don't have 20k plus invested in mics.
I guess if it were me and I found I generally chose one or 2 of the simulations constantly, I would look into buying a non-virtual version of it (or a good clone) if it was within my budget.
I am not a Producer.
I merely provide a decent Studio and the Equipment for folks to record their raw tracks in my rooms with my mics, and then they cart the raw tracks off to do their thing with them in their Home Based Studios.
So I need actual microphones.
Having said that I have still been tempted to buy one for trying to cover mics I have yet to buy (C800, ELA M-251) that I am not sure I want to invest in.