They both have their strengths .... and their weaknesses.
At times the Korg sounds boxy.. and at times the Yamaha sounds lifeless..
Surely there is no edge going to Yamaha from me... concerning the drums.. Are they better than they were 20 years ago.. Yes... better than other brands.. No..
They each have some great lead sounds... and clunkers too..
Styles are just styles to me... they each have usable styles and many I would never use..
Neither compare to their Big Brothers... It has always been the case.. some folks can't hear the difference because they don't want to..
The Korg PA1000 and Yamaha psr s975 are not on my wish list..
First I do not prefer the sounds to what I have..
Secondly, They lack of features that are important to me (like reading chords extracted automatically from files). Korg stated it can ..but does not... you need to prepare the file to show chords..
Yamaha still has the worse playable keybed..(close tie with Casio)..
We are now talking about $2,000 keyboards.... sorry I want top models for that price.... and yes you can find them... People love to lose money (cost of doing business)..