I like the Pianoteq very much. It is based on physical modeling, so "Layers" and 'samples' do not apply to it, and it can do very soft passages to loud very well. Low notes and high notes also.

I also feel my MIDI keyboards don't do it justice, and so would some downloaded MIDI files, for, how were they created? With a good responsive MIDI keyboard or with a regular low-end one like mine?