Having listened to all the demos posted on this and other sites of various brands of arranger keyboards and synths, plus playing a pretty good number of the latest arrangers keyboards first hand, I've always felt the definition of a "LIVE" sounding keyboard was one that was one where the sounds were harsher and unpolished, somewhat louder within the styles themselves, and sharper sounding, often to the point of being a bit distorted. Now, I have yet to hear the 900 in person, but I have listened to a lot of demos. Personally, I don't hear enough difference between all of the MOTL and TOTL arrangers to sway me one way or another, and if I'm not impressed, I know my audiences will not be impressed.
From the standpoint of a full-time musician/singer/entertainer the question that begs to be answered is "Will I sound any better to my audiences?" For me, the obvious answer is NO! At least not enough to make a significant difference and justify the financial outlay involved. But, maybe I'm just a lot easier to please when it comes to these situations. I would much rather put that money into my retirement account, which my loving wife of more than a half century will eventually withdraw and leisurely piss away on jewelry or some other crazy things. I guess that's why every time I go out and test drive another keyboard she always says "What's wrong with the ones you have?" Of course, I try to evade the question, but she is absolutely right.
Cheers,
Gary