Don't buy it! Imagine the things you can do with a master keyboard and a basic computer with even a cut down entry level real sequencer. Then imagine doing those things with buttons, and no mouse, no VSTi instruments, no expandability and a very restricted and finite upgrade path. These things are good for a one man band in a pub, who is a master of dexterity, who can sing, play and press buttons all at the same time. A jack for a mic input? That's a clue. These things let you put together tracks for live use, but Yamaha have some excellent sounds and some truly naff ones. They can play a GM track sourced from the net quite pleasantly. They can let your programme robotic drum and bass, but they are complex to use, restrictive and a niche product. Please forgive me, but they're about as much at home in a studio as a person with garlic breath and the habit of farting all the time.
For the price - they work in a one man band in a bar or pub with an audience who don't care much. The youtube demos concentrate on a few nice sounds. other video reveal the old fall back - press a button, a pre-programmed rhythm tracks appears and you can play chords over the top that play a pre-programmed twiddly bit.
I found this video - showing it's designed to produce pre-programmed nice sounding stuff.
YouTube
As a music production tool, and for recording and real studio stuff, it's the wrong product. If you want to entertain to a non-discerning, easily impressed audience - then it's a one box solution.