Font Manager Suggestions

I was curious to know what people thought of the various font managers that are around right now. The last time I tried to use Font Book with my abundance of fonts, it FUBAR'd the default fonts, and I was forced to see all sorts of strange characters in Firefox, iTunes, and several other apps. I am assuming these can help with preventing said FUBAR, and before I invested in one over another, I wanted to get some opinions from fellow Mac users.