I've not had the fonts disappear, yet, but other things have gone wrong.
In Xfce I like the combination of the Agua window manager, Leopardish Theme and LeopardX icons, but with Xfce 4.8x, there was a problem with the mouse cursor and window manager disappearing from one sign-on to the next.
I thought that was all behind me with 4.10, but just a few days ago, the exact same thing happened again. So I deleted the configuration files and started over from scratch using all the defaults. It happened again 24 hours later.
So, I rebuilt it again, and again, I'm using the defaults, but if the mouse and window manager go missing again, Xfce is going into that great trash bin in cyberspace.