I joined Reddit in 2005 and liked the format. I had been self-hosting Mastodon for a while before I joined Lemmy because it had long been evident that a centralized corporate internet is not exactly great for its users or the world at large. I had also experimented with Hubzilla and Akkoma.
I looked at Lemmy a couple times before the Reddit API fiasco and it was just a couple servers that were dominated by people who thought Stalin did nothing wrong and killing Uyghurs is just fine and/or not happening. I was not motivated to participate at that time. When lemmy.world launched, I joined it because I had the impression mastodon.world was well-run.
I tried Hubzilla, Akkoma, and Mastodon. I still use Mastodon. I have the ActivityPub plugin on a Wordpress site, but haven't yet migrated that site's Mastodon account because Wordpress doesn't offer a great experience for consuming content from accounts I follow. I may try out Wafrn.
I've always had mixed feelings about the microblogging category. Low friction to post and interact is good. Character limits and a complete lack of formatting, not so much. I set the character limit on my self-hosted Mastodon instance to a big number I never approach; I routinely exceed the default 500.
I was aware of Lemmy for a while, but didn't join until the Reddit API fiasco because most of the activity was weird political extremism until suddenly a ton of people wanted Reddit alternatives and new servers sprang up.