I bought the app.
I turned my Yamaha psr ew400 with a dull hard to read screen into a
76 note keyboard arranger with a 7.5 inch touch screen, unlimited styles. with my korg pa600. I have a nice setup. not bad for a 29.99 app.

I had One-Man-band many years ago.
Is the app anything like GarageBand app?
Are there styles presents or do you have to build them?

Thank you, John C.

It comes with styles, plus you can download thousands of Yamaha styles available on the net. Some of my own created styles need some work, but over all it plays the majority of the styles. Yes it has limitations , ( like some editing features) but I'm happy with it . Fun to playaround with.