I've had numerous digital pianos from all the major brands for the last 20 years and I've tested almost all digital pianos I could get my hands on. I've learned on an upright piano as a kid and I've also played many grand pianos. I play mostly classical music, romantic repertoire being my favorite. With all that in mind the N1X is simply the closest thing to a real grand (along with its bigger brother N3X and probably the Kawai Novus NV10 which I haven't tested). It's miles ahead of any of the regular digital pianos including high end Clavinova pianos, Kawai CA-series with wooden action, etc. The difference is striking both from touch perspective and sound. I've never been so happy with a digital piano! The CFX and Bösendorfer patches sound great through the multichannel speaker system and I'm easily fooled into thinking I'm sitting behind a real grand since the sound is projecting from the entire body. The bass is tight and controlled, clean and distinctive, it's not the boomy mess you get from other digital pianos. The VRM resonance modeling is a pure joy too. And of course the real grand piano action! All that makes for an uncompromising piano experience. The CFX binaural patch is stunning through headphones and I often have to remove the headphones to make sure the sound is indeed coming from the headphones and not from the speakers, so real and three-dimensional it is! The only complaint I have is that the other piano voices while great through speakers, are slightly thin through headphones. But the CFX binaural makes up for that. Harpsichord is the best one I've heard and that's a nice bonus. I would have preferred if the button panel was hidden so that the piano looks like a real piano but even now it's still very unobtrusive and the display turns off after a few seconds so it's not a big deal.
I took one star off "features" because some functions require button and key combinations and the display is too outdated. On the other hand, it's an acoustic piano replacement, not a synth workstation, so it's meant to be played, not tweaked. But a better interface could have been better. Another reason for the 4 stars is there's no embedded Wi-Fi and one needs to purchase a separate dongle from Yamaha in order to use the iPhone app.
I can't find enough words to praise the N1X. It's probably one of the most successful product choices I've ever made. Highly recommended piano.