I'll be adding support for more types and customizing the color choices soon. You can opt-in to pretty-printing with your own objects by implementing a to_printable() function. I'm brainstorming ways to add support for not-your custom types as well (for example, Pandora Entities) - I have a few ideas but nothing implemented yet.
I've been using it in my own projects for a few months now, so it feels ready to share - I'm hopeful that others find it useful!