Hi,
I actually paid to haver a MIDI retrofit done for the Baby Grand ( Zimmermann ) in our house around 10 years ago.
It was a Quiettime Magicstar system.
It served me very well but there are some caveats worth bearing in mind when doing this to a piano - namely that it does slightly change the action and make the travel a little reduced. This can result in a slightly heavier action than before. And I think this applied whether the silencing bar was being used to silence the piano or not.
I suspect that the pianos - primarily Yamaha but also KAWAI and recenrtly Steinway - where such MIDI silent systems are fitted from the time they are in factory and the pianos can be designed with dimensions specifically tailored for the silent MIDI system and its sensors, that such pianos will be better as compared to retrofits.
I gotr many years of use out of my MIDI retrofit - used primarily with Ableton, but it has to be said that the MIDI sensitivity and response was good but had lmitations due to the way such systems work - and a good new designed MIDI controller such as made by KAWAI ( considered by many to have the best actions these days ) will be far better. But of course wont give the joy of being a real piano.
Also it needs to be said that my Quiettime System was v4 and a much more recent iteration of those silent piano systems is being made and sold these days by Pianodisk that i believe has much better and responsive sensors. So maybe things have improved a lot.
But even though the sensort nowadatys in such retrofits might be much better there is still the issue of how adding such a retrofit does physically change the actual real action mechanism a little.
My mother - who is 93 found it too hard to play the retrofitted piano due to the very slight incvrease she said in the stiffness. But having said that - I found the action in tewrms of stiffness no different to the FATAR 88 key mechanism in my currrent KOMPLETE KONTROL MK II 88. controller keyboard. But then i'm a little younger and not a trained classical pianist.
My mother now has a great value KAWAI ES110 piano and I have to say I absolutely love playing that thing. So you might want to consider any controller keyboard that uses KAWAI. the VP1 dfor example. Plus NORD released rhe Grand recently which has a KAWAI mechanism. Not a real acoustic of course but very playable.
Just my tuppeneth - having actually paid for the MIDI retrofit you mention.
regards
Dan