I've no direct experience with them Stuart, but this will put you back up to the top and perhaps someone will come along who has/does use them.
They appear good value on the surface though.
Are you certain that you need multiple MySQL databases ?
I prefer to keep user authentication in a separate database to other content for e-commerce applications, but you don't need to do things this way and one database can and will run the whole show.
Anyway, this goes back to the top and hopefully you'll get some kind of answer.
God luck with it.