libfive is great! And if you're into SDFs, libfive will give you something Bauble probably never will: the ability to export shapes as meshes, so you can 3D print them or import them into Blender or whatever.

libfive is only concerned with geometry, though, so you can't do any of the coloring/shading/procedural graphics stuff. And no animations. I think of Bauble as closer to Shadertoy than libfive in purpose, although they appear very similar.