With the loud note issue fixed, I'd say a NU1X is actually even better than a real upright
Because on a real upright the same scenario results in a silent note (or a very faint note due to jack sliding over the butt and would eventually still push the hammer with a very low velocity due to the friction). However with the fix implemented by Yamaha, assuming they fixed it in the way I proposed and Herq implementing it, the resulting note volume would be neither loud, nor quiet and most probably repeats the previous note. I strongly believe that's something piano creators would have liked
Because although the key suddenly lightens up, it still produces a proper note
I might be wrong though.
I think they actually did a better job. Which is not surprising given their resources and the fact this is their business. The implementation I had was kind of an on/off thing, such that if the timing didn’t fit the predefined parameters the fix wouldn’t do anything and a loud note could still sound (like with Gombessa’s example). Now the thing just works. And like you said, a note still sounds, instead of being completely silent.
I’m very satisfied both with Yamaha in general and with their technical support. The piano services supervisor handling my case was very professional and direct to the point.
I was also about to get back in the market because this issue was driving me nuts. I’m now a happy owner, I’ll stay with the NU1 for a few more years and will likely not hesitate in purchasing another Yamaha. And hopefully, with this problem fixed, the NU1 will no longer lose too much of its value when it’s time to move on.