The Antarese Mic Mod EFX offered something similar, although at about twice the price.
The promise of being able to get in the ballpark of some famous microphone definitely has appeal.
These programs have to do two things -
remove the color of the original microphone, and then
add the color of the emulated microphone. To do that, you'll need to get a fairly neutral recording in the first place.
On the other hand, it's encourages people to believe that what's important about other microphones isn't that they are more
accurate, or can capture more
range, but that the circuitry performs magic processing which imparts a poorly defined "warm" quality to the vocals.
It seems to me that if you want to "color" the sound, you should have a very specific sound in mind, and be able to get there with EQ and such.
Then again, that wouldn't stop me playing with the plugin if I had it.