the thing about emulators, is....
they can make the RECORDING sound authentic.
but they can't make it FEEL right.
at least not for a typical rock guitar rig,
where you are making the hair on your legs move.
this is where the mojo is,
when you engage the environment with the sound.
the strings of the guitar vibrate on their own,
the internal dimensions of the speaker cabinet come into play,
the sonic fingerprint of the room becomes important,
the impact of the sound gives you butterflies in your gut.
i've played some pretty cool emulations,
and i think they are really good tools for really good players.
but micing up a real rig is the dealio.