I have tested the PX S1100 for quite an hour at a big shop in Italy. These are my impressions.
Action: the so called “black key issue” is absolutely non-existent. Yes, if you play the black keys on the very tip of them, you can perceive a little difference in weight, but noone plays black keys on the very tip. For all kinds of genres and playing technique, the action is perfectly fine. Apologies for the doubts I have expressed in my previous posts: in a practical situation, the action is absolutely flawless.
Acoustic piano sound: a nice, bright (but not metallic) and round Steinway. Very good dynamic range, excellent resonance engine. Maybe a little “digital” in the bass compartment - but this could be due to the speakers.
Other sounds: very decent palette.
PA system: a little weak, not in absolute terms (8Wx2 could be absolutely fine for home usage) but in terms of bass-mid bass roundness. But for the kind of instrument (and for the price point) this feature is absolutely acceptable. I like the little “cracks” on the front panel that - if I have understood correctly- allows some sound to reach the player directly. I wonder if there is some EQ adjustment with Chordana that could improve the bass compartment.
UI: elegant but rather poor, better to use Chordana to manage the very complete instrument editing capabilities.
Connectivity: I am still not comfortable with the decision to use the same USB A port for USB audio recording and Bluetooth dongle. Given the fact that S1100 has lost the line in, now it is impossible to record your performance while streaming a backing track. And I assume that the instrument can only receive audio over Bluetooth - not send it. Maybe audio over USB could solve the issue - but I doubt that this feature could be implemented through a future firmware update.
Overall: elegant, modern, sleek, light, good sounding, relaxing action - a very good bang for the bucks.