My biggest concern when I first came over and had a look at Lemmy was the fact that all the main Lemmy instances had big "No Porn!" rules front and center. Porn is the lifeblood of a free internet, and the foundation of human inventiveness and drive for innovation.
Fortunately that seems to have largely been swamped by the Reddit refugees. Along with the disturbing prevalence of tankies, the second biggest concern I had when I first came over and had a look at Lemmy. Things seem to be well on track now.