I have the Full TP and he diamond module sounds very good to me.
Tp is modeled not sampled that is why you do not get a different sample when playing quiet.
I have NI The Grand as well and there are things I like about it also like the sympathetic resonance. That feature is in TP as well but I do not hear it.
I have a controller in another room that has all 3 pedals At some point I will hook it up to my laptop and see the pressing the Pianissimo pedal has an effect on TP.