My understanding is that it is fairly subtle but gets less subtle as you turn up the drive. Also, if you put it on all tracks, including the buss tracks, it also has more of an effect.
I was curious as to what it did so I loaded up a track, cloned, inverted and then turned the console emulation on for just one track. If you do this, you can hear what it is doing.
There is also another posts here (several actually) that go into it in more detail. There is one that shows spectral analysis so you can "see" what it is doing to the signal.