I own my fair share of electric pianos. I have a Rhodes 73, a Hohner Pianet-T, and a Wurlitzer 200A. So why did I want to buy my friend Ben's CP-60M when I found out that he might be selling it? For starters, the CP-60M is actually an electric PIANO, where the others, although called 'electric pianos', are more like electric music boxes or an electric celeste. The Rhodes, Wurlitzer, and Hohner all use tines or bars to create their pitch for each key, where the Yamaha actually uses strings.
The advantage about this over a sample of an acoustic piano is that this instrument doesn't have to be perfectly in tune. Sometime, you want a sound where some of the keys are slightly up or down in pitch - not out of key, so to speak, but just detuned enough to add some chorus or beating to the sound. This makes for a rich, beautiful sounding piano. If I want something perfectly in tune, then I will reach for a sampler.
I have also been using this with a vintage "harpsichord bar" that I bought and cut to fit the CP-60M. This bar dangles a piece of metal in between the hammer and strings to make the piano sound like a harpsichord or "thumb tack" piano (thumb tacks onto the hammers of a piano give the same results). The advantage of this bar is that it is easily removable so you can change back and forth from piano sound to harpsichord sound by lifting the bar.
A few more things to mention about this. The "M" stands for MIDI and although this does not have a MIDI input and solenoids to actuate the hammers (that would be cool), it does have a MIDI out to also layer other sounds along with the piano. Another great thing about the CP-60M is that it has a nice built in EQ to make the piano pickups sound as bright or as dull as you wish.