Unplugged styles on Korg are great. It's nice you can delete or edit factory styles.
Ketron sounds most live.
Yamaha styles do a lot FOR you. You have to be careful using their intros and endings because most people can't play that well, and they are EXPOSED!
I've never had a problem finding all the styles I need for any arranger in the past 7 or 8 years.
There may be a hundred thousand for Yamaha out there, but MANY are the same, renamed, slightly tweaked. They have quite a few generations of keyboards that use the same styles, maybe renamed, tweaked a little. Then people convert them for optimum use in older models, or tweak older styles to use in the new ones. Lots of people find a style, change the tempo or something and name it after a song. Doesn't make it a song style though.
How many styles do you NEED, or use? Maybe way fewer than a hundred. . . certainly not a thousand.
Just rambling.
All the newer arrangers have great styles. Depends on what you like to hear.