Disklavier

Hello,

I am hoping to get some feedback on the Yamaha MIDI piano line.  I am
leaning towards purchasing a MIDI piano for several reasons:

1. It doesn't do playback (which I don't need, and I don't want to run
into maintenance nightmares with the solenoids going bad).

2. MIDI models are cheaper than the Disklavier models.

3. You can play/hear the acoustic piano at the same time as the MIDI
digital sound is pumping out of external speakers, something the
existing Disklaviers can't do (which is great for performances).

About the only downsides to the MIDI pianos that I can see are that
they are usually special order, and they only come in MPC3, MPC6, and
MPC7 models (no C5 model).

My question is, mainly, is the optical sensing technology on the MIDI
pianos as good as the sensing technology on the Disklaiver pianos
(including Disklaiver Pro models)?

Thank You,
Eric

P.S.  If anyone is selling a Yamaha Disklavier or MIDI piano please
let me know.