I'm testing it on a "live" backup install with a limited library right now and so far, so good. We'll see how it does before I put it on my main machine. 🤭
I have a setup with a small library that I take with me on the go. If it gets messed up, No biggie to burn it and set it up again, esp since some of the other 10.9.* bugs included deleting media files.