I think in general you can recognise the styles because of sound and arrangements...
Recognising which keyboard is what because of a single sound is near impossible these days...
And while the simple samples of the ketron do sound good, i prefer the yamaha sa2 and Roland sna because of the real time expresion you can archieve with them and the several different articulations they give acces to for a single sound.. But does the single samples of those sounds sound better then Ketrons?