If you're happy with Lemmy then don't.
This is mostly a mix of personal preferences and neat little differences I enjoy, plus I like the local community.
IMHO much better integration with the rest of the Fediverse, it supports note type activity (posts without a title, thus supporting most of the Fediverse), it supports adding tags (#hashtags) to threads, it also supports boosting posts and a few more things like that
the point of mbin wasnt originally differentiation of any kind, it was that the lone kbin dev did not share duties, or actually develop on a normal timeframe. this behavior kept kbin from flourishing and implementing all kinds of suggested, developed PRs.
it was forked to mbin as a community project where anyone who wants to contribute basically can by committee instead lone stewardship.
you would need to check the repo for all the changes per version... but the best part is, its an active dev group.