Hi,
I've always wondered whether a singer requires a fuller ( more complex type of style (I'm not a singer) as opposed to a player who uses an arranger to play melody and backing.

I've had many arrangers over the years. Personally ( for my taste in music( latin , bigband etc rather than more modern stuff like rock , pop etc) I used to find some of the Korg & Roland styles over orchestrated for playing along to, wheras, I would imagine, if I'd been singing along to the style rather than playing along, they would have been wonderful.

I think the point I'm trying to make is that you have to identify what type of music you prefer to play, and whether you sing or mainly play. Each keyboard has it's pluses and minuses when it comes to styles, some sound great for the more modern stuff, others are better for jazz, latin etc.
Some people find Yamaha styles too simplistic whereas I never had a problem trying to find a style to go with a song on my 9000 pro, I couldn't say the same for my korg or roland keyboards.

best wishes
Rikki