I've just switched to mu4e. It's unbelievably great, thank you everyone who's recommended it over the years.
However, I would like to compose my replies in org-mode and send them out as HTML. I guess the older tools for doing this are officially deprecated. Nonetheless, does anyone use them? Would you be willing to share your workflow, and thoughts about what pain points you still have?? I see John K. has written some cool posts about, e.g., sending headings out, but not about org-ifying the compose buffer.