I think another big difference is Lemmy still feels like it is inviting at least a small amount of conversation. Whereas Reddit increasingly feels to me like it collectively prefers to upvote only one correct answer, and stamp down everything else.
I think with federation in general we have more of a chance to preserve what we value in each instance. Whether that is constructive conversation, or cited responses, or memes only/ no memes…
I look forward to being a part of multiple, quite different feeling networks of communities.