The major change in the new Illusonic firmware is to the depth/immersion parameters of the Illusonic ,essentially the IAP processor separates direct, reflected and ambient sounds.
The new version has three parameters, 'gain' strength of immersion, 'high' - brilliance and 'size' which is the size of the virtual room.
The effect is one of incrediblely extended spaciousness , it isn't an audio 'effect' but to 'feel' the acoustic of the recording.
http://www.illusonic.com/
Keith