I still hang out mostly on Reddit. As much as the site’s gone downhill, I’m mostly active on the fandom-specific subs, which don’t have nearly as much of a presence on Lemmy. The general meme communities have been flourishing, but the fandom communities are basically ghost towns, and even those that see a bare minimum of activity are far from enough to pop up in my feed. Right now, /r/yugioh has ten times as many online users as /c/yugioh has subscribers period - and that’s one of the more active niche communities I follow! I’ll still be keeping an eye on Lemmy and post to both sites when I can, but we’ve got a lot more growing to do before I’m ready to finally ditch Reddit.
Also, Reddit has the hentai. The specific fandom subs at least have small barely-active communities here but their NSFW counterparts are totally nonexistent.