The really amazing thing about digital recording is that the track goes directly into a software program where you can manipulate your performance - if you released a note too soon, you can extend the sound or shorten it if you held it too long, if you play a wrong note, you can delete it and insert the correct one, adjust tempo, etc. I recently recorded a 4-hand (Faure's Dolly Suite) with a relative on two separate digital pianos in two different rooms, using headphones. The result was pretty damn amazing and the beauty is we could play with the tracks later and adjust them. I know it all sounds dishonest, but the technology is here to stay. PS: we were using a small professional recording studio with all the bells and whistles so the above was facilitated. For best results you really must use a good digital, weighted 88-key type (Yamaha, Roland, Kurtzweil, etc.) You can experiement with piano samples until you get the one you like.