I purchased their products before. I do not like their licensing scheme at all, and so I decided to not purchase any more of their products.
Usually the expansion packs directly published by Yamaha come in with PPF and PPI files. The Yamaha PPF files allow us to install the same expansion pack for multiple Yamaha arranger keyboards without additional cost.
ProStyle Music (PSM) licensing scheme is very strict, the CPF file will install in YEM for only the one Yamaha arranger keyboard you register with them. If you own more than one Yamaha arranger keyboard, you will have to pay extra for the same product. Their expansion packs only use their own voice samples, and so we cannot easily modify the voices of their styles to be used on other Yamaha arranger keyboards.
Thanks,
Paul