Hey, I'm Avi! I created HEML You are 100% correct MJML has more features at this point. I think that the biggest sell of HEML over MJML is the way styling works. HEML focuses on letting the user style with CSS in a very native way and works to make that CSS as email-ready as possible. It also wraps a lot of HTML elements to make them safe for sending. MJML abstracts everything away to the point where you start to lose a lot of features of HTML and CSS, while also forcing you to learn their specific styling paradigm.

In the end, the goal is to make it easier to build better emails. If MJML does the trick for you, then that's absolutely what you should use!