The Rocky is a very old design. It was great 20 years ago. Things have moved on since. As for The Lelit grinders… I don’t know. They don’t appeal to me at all. I don’t like wasting coffee, so most of the traditional grinders in their standard shape and form don’t appeal to me due to retention - of course some are better than others. Some modify ex-comercial second hand Mazzer grinders for single dosing and enjoy the results.
It all depends what you want, and it would be best to do your Research. The Niche is very popular here, or maybe the DF64 if you value single dosing.
Anyhow, as said before, if you already bought your machine, see how you get on with your MDF. If you Google, you can modify it to be stepless so it might have another lease of life in it. 👍