I think it's okay alternative - not many unique features apart from federation/decentralization. I mean Saidit has two types of upvotes/no downvotes, chat; Notabug was real-time (you didn't need to refresh post to see new comments), had "spaces" moderation model, topics instead of communities (which were auto-created at the moment of submitting post), very fast chat built on the same engine as comments page, anon posting/chatting, PoW voting.

And Lemmy has what?