I have a few large React apps that have been using mostly Immutable.JS from the very beginning, so I rarely run into issues where I need to think whether what I'm dealing with is an Immutable.JS object or plain JS objects. I can see an issue if you are incrementally converting an app to Immutable.JS and dealing with a mix of plain JS objects though.

I have heard criticisms of lisp macros as making it a write-once language. If you're not working on a team then maybe it's fine, but other people aren't gonna want to figure out how your macros work.