Old video that has been posted here at least once or twice before but still a goody.

I too am very certain its the stock standard Grand X voice. It is without a doubt just as good as any piano voice on any top level keyboard out there today. its not a matter of which is "better" but more of personal preference.

I have owned and played MANY different keyboards and synths and the Grand X voice played on the G70 is my favourite to date. The keys themselves on the G70 is what also adds to the quality.