I don't own one, but while searching for an instrument, I played an F183, 2xF212, 2xF228, and an F278. I strongly considered an F212 that was being offered for slightly less than SMP of a Steinway B. These are my thoughts after spending ~6-8 hours playing the above instruments. Take with a grain of 🧂.
The Fazioli touch and tone is definitely unique; you hear and feel it right away. The first thing I noticed at each instrument was the incredible dynamic range under your fingertips. They are LOUD instruments, with a much greater controllable dynamic range in the f-fff range than any other piano I've played. Of course they can also be played quite softly, but the extra degree of control at the top of end of the dynamic range is what really stood out to me. You have so much power in reserve. It's like driving a race car.
The bass on all of the instruments I played was full, powerful, and clear. More robust than any other instrument in their respective size classes. The tenor and treble are clear and pure without sounding harsh or shrill. The attack is warm and soft - not a hint of the metallic pinging you can sometimes get on bright/clear instruments.
The fit/finish is immaculate. It has the most beautiful finish on a piano harp I've come across, a deep gold color that sparkles with transverse lighting. Truly breathtaking.
The tone / harmonic profile is decidedly European. Fazioli trades the lush harmonics you might find in Steinway for clarity. But unlike most other European instruments I've tried, it does so while maintaining a sense of warmth, in contrast with other makers' instruments that may end up sounding cold or harsh in their pursuit for clarity.
In my personal opinion, the "weakness" of Fazioli is a more limited color profile throughout the dynamic range. The difference between pianissimo and fortissimo with respect to volume is enormous, but the tone itself doesn't change all that much. American Steinways sound fuzzy, warm and lush at pianissimo, become a bit more clear and bright when pushed louder, and eventually the tone strains and begins breaking apart when you really push it to ff and beyond. A Steinway will shout with you. A Fazioli just sings louder. This comes down to a difference in philosophy surrounding how the piano should ideally perform. For me, I prefer the Steinway approach and feel more tonally limited with Fazioli. Others may admire a tone that remains pure regardless of how hard you push the instrument.