Hi Glyn,
You can install the update over an existing install (plugin first... then the Atlantis module)
To my ears, the Atlantis module sounds more realistic in some ways... and very artificial in others.
The lower mid section notes... and higher notes played staccato sound artificial to me.
Overall... I prefer the Diamond/Jazz
Being that this is a preview release... I'm sure 4-Front will further tweak the module before releasing True Pianos v2.