After a "bumpy" start with the SX900 OS, studying the manual & reference manual, checking SX900 related posts on PSR Tutorial and Eileen's Keyboard Players site, trying to figure out the style categories and getting some first hand help from SteveM, and installing the latest upgrade....I am enjoying playing it and recreating registrations and voices that work with the "bread and butter" repertoire needed for the gigs, that are now on hiatus.
Now that I understand it a little better, it really is fun to play using the assignable buttons and Live Control knobs. Love the speakers too.
My S970 stands ready if a call comes in and will do just fine until I get the SX up to speed.