Interesting, I am the opposite, in that I find Yamaha styles to be too song specific (Including the factory ones) with few that can be used for general use. In addition I find Yamaha styles to be the least realistic in giving the impression of having a live backing band, but instead sound like a canned CD. (They are very easy play though, so you can sound great with minimal training)

Korg on the other hand sound live, (As if you are listening to a live band) but it does mean you need to know more about the music to really put things together. (Practice and learn and you will find the Korg will reward in spades)

Personally I hate the all singing all dancing type styles as they just get in the way of playing. (You have to adapt to the style, rather than the style just enhancing your performance)

Just goes to show how personal music is.

Bill