The best I have for you is stop thinking Yamaha. Going from one major keyboard to another requires a clear mind that is not trying to follow the systems of their old keyboard.
My trip form Technics to Roland and Yamaha was not too difficult, but I found Korg to be a different animal. Why is it difficult? Because, in my opinion there are far more options. Korg�s manual is not friendly but it does have your answers.
My need to get the Pa800 ready to use on a job brought many frustrations.
Over 12 years with Technics I should have the OS down pat. After a Psr900, Tyros 2, and a Tyros 3 I had no problem with the OS. My advice to you is to learn one area of you Korg that�s the most important to you then go on to the next.
I do not regret, no better still, I feel real good about Korg, I�m glad I put the time in to understand the keyboard
In My Humble Opinion, John C.