Things that made me choose SD1:
 very realistic styles and sounds
 HD storage and quick access for practically unlimited number of personal settings, new styles etc…
 stack of four independent sounds for right hand
 footswitches for various functions
 onboard vocoder
 support for midi accordion
 76 keys

I would by another Ketron:
 because of the above reasons
 stable hardware
 very good support and ability to repair, change and add SW functions

What I would like to suggest for future implementations and models is a mode (controlled by a footswitch) in which keyboard would be able to follow the tempo played by musician (to make accelerandos and ritterdandos).

Luka