One word: perfection. Altough the 'strings' intrument is not quite state-of-the-art, I think in case of a digital piano I should focus on the piano sounds, which are EXCELLENT. And I mean the acoustic piano sound. The loop portion of the samples are pretty short though, this is only apparent in the lower ranges, where sounds do not evolve and resonate over a long period of time. But I think Yamaha sound engineers did their job well enough, a BIG THUMBS UP!
On the issue of "ringing" mentioned by others: I think my model has that too, but such a technicality does not have a negative impact on my listening/playing experience. It's the resonance of the metal encasing the microphone they used while recording I guess. For those who are scared by this: I still rate it as 'pristine sound quality'. It's almost impossible to notice - only when you're paying attention to that, not the music. I consider it part of my piano - as you could hear a singer breathing or you hear pages turning during a pianissimo passage.
The speakers: I am satisfied with them. I wouldn't call them a "joke".
Don't expect big basses coming out of them, but apart from that, they excell. And one more thing: when using speakers, those short-looped low notes start to become more lifelike. Maybe that little resonance the body of this digit piano can produce is enough to do some magic.
Expresivenes: perfect match between the action and the sound volume/harmonic content. That simply.
I have been owning it only for 2 month now, and we hade a 400 km bumpy ride from the store (and digital pianos don't especially like bumpy rides). I think I won't have any issues with it. Absolutely robust. Dependable. It's a Yamaha.
Definitely would gig without backup. Could be a bit lighter, though :)
It is certainly worth its price. I was looking primarily for a hammer action keyboard, but what I got is something more, an _instrument_, which has a 'life of its own'. I can turn it on any time if I want to play. No 'turn-on-the-computer-and-load-some-softsynths' fooling around. I have a masterkeyboard/DAW pc/sound modules system, so this is my first 'standalone' unit. I can take it anywhere, anytime. The overall feel: the looks, the sounds, the action is incredibly inspiring. I recommend for everyone looking for a digital piano:
altough it does not have string and soundboard resonance, key-off samples, half-pedaling effects, I would still call it a _complete_, robust, perfect, beautiful digital piano.