There are, or at least there were, two variations of EMC Styleworks. Universal, which is the one I have, lets you convert from almost any make to almost any make. Mine is an older version and didn't originally have support for later instruments such as the BK series and the later Atelier organs. I cheekily asked if I could have an upgrade and one was provided free of charge. (I can't guarantee that 'free' applies to everyone, remember that I work in the business and my reviews of the software helped sell many copies!).
The second, and better priced version is for one make only. So if you want to convert from almost anything to Roland, you buy the Roland version. There is, as has been said, some tidying up to be done and as Roland don't offer much in the way of style editing on board, you need to get it right in the software. But you can do this as many times as it takes to get the right sounds and balance. I've converted a few from the PRS-S series to BK5/Atelier and, after a little work, they sound OK. Not as good as they do on the Yamaha but a good addition.