I use a Kawai piano as a MIDI controller. Then again, I'm a classically trained pianist and often I just play the piano. No synth gives the full piano experience in the same way - keys action, soundboard resonance, pedals, vibrations through your feet... I guess those things are important to you or they're not.
The top of a piano real estate makes for a great synth box setup, so my piano doubles as a kckass OTB workstation hub. If I were just after a good piano sound to multitrack, though, I'd buy Modartt Pianoteq or Kontakt and be done.
Less words more noise