Here is some unsolicited advice from a killjoy for all those considering a SX900. The SX900 is not going to be a "night and day" difference over the old PSR-975.
I hope to demo one in the next month or so maybe even sooner. For me the better keys, the touch screen, assignable buttons and the playlist feature are enough for me. I’ve had quite a few arrangers and I’m not that naive to think this will be a revolution in sound from Yamaha, besides it’s just fun to reward ourselves with something new, I don’t drink, smoke, gamble or womanize I need some kind of vice