I think Mise is better than ASDF - they have a whole document on why their approach is better than the shims used by ASDF. Both seem fine though.

How does it handle the wx stuff and whatnot that's required for Observer?

Seems to have more project management and make-like capabilities, I can see why someone might find that attractive but it's not for me.

mise should get precompiled erlang on macos today too