I've tried them both out, though not for very long. I can't really explain why, but the korg seemed a lot more professional. Maybe it was the cheesy icons yamaha puts in. Or maybe its those subtitles on all the voices ( like "cool!" or "live!"). But for some reason, when i used the yamaha i felt like i was using a toy. The korg feels like a much better piece of equiptment. Now that's where I'm really stuck, Because the Korg is like $800 more expensive. I dunno if it's worth it for me to spend $800 because I don't want to use a cheesy keyboard. I mean overall they seemed pretty equal as far as vocies and stuff. But then again you could argue that as a keyboardist, its important to have a keyboard that feels right, even if there is no specific reason why it might be better. Hmmmmm... anyone have any input on the matter???
* The korg did have this ammmmazing organ. It was like a Percus something. I'm in love with it!