Hi,
it's actually a realtime arranger software, but it has some really good stylemaking tools.
There is a demo on Jos's site but I don't think you can actually save stuff, but at least you can check it out.

It's the stylemaker section you'd want
Window
Stylemaker ( section )http://www.1manband.nl/omb.htm

I originally bought it so that I could create midifiles of psr styles and then convert them into styles for my kn7.

Anyway that's how I discovered it had quite a few similar stylemaking functions to my kn7. My KN7's gone, now I'm basically using omb for style editing & creation, (plus using it as a realtime arranger midied up to my clavinova.)

If you're basically happy with your Yamaha arranger, it might be worth checking omb out.

best wishes
Rikki