Top me it sounds like it's playing over the exact same rythm, that it's 'only' the lead vices to compare?
I think it's about personal taste, and in my ears Korg was warmer and softer than Yamaha.
Yamaha has a crisper and clearer sound, more CD'is or effects at it.
But at the end, SX took the lead in my ears this time. 😎