I posted a comment, one of my first, about something I think would vastly improve the user experience. I stand by it 100%, what I describe there was by far the most confusing part for me. I think the new user guide in general could use a pass-over by people who aren't tech savvy and are going to be more "casual" users, right now it's quite long and IMO a bit too technical for most people. It's too much all at once.
Now that I'm past that, I'm finding it quite similar to reddit. The biggest "problem" so far is that it's so small, so a lot of the small reddit communities I was in are non existant. I'm not comfortable moderating (I don't really have the time), so I won't make them myself, but I will miss them. Tbh for some things I'll probably still use reddit on desktop (until they kill old reddit) but lemmy on mobile.
My biggest concern from the beginning, and the reason I joined a big and established instance, is what will happen to people's accounts if their instance gets taken down by the creators. To me that seems like a kinda fundamental flaw here. I'm really not sure how or if it could be fixed, either.