Lemmy and BlueSky (primarily Lemmy).
BlueSky’s mobile app is such a clone of twitter, transitioning is nearly seamless for the average user. I tried mastodon at first, but it felt pretty rocky and different (and I’m rather techy).
Between BlueSky and Voyager for Lemmy (I was an Apollo user on Reddit), my user experience hasn’t changed at all – except for the pleasant lack of bots and Nazis on both platforms.