For me I started on lemmy.ml because that is where you get kinda herded to when you come initially. I don’t know if it’s still clunky, but when I was on there it was slow. Tried lemmy.world a couple days later and it was smooth as butter. My goal was the smoothest experience after the initial impression I got from lemmy.ml I was worried. But lemmy.world was way better. Been here for a month, lemmy.world went through a few server upgrades and the reddit hug of death on the first, but either they handled it pretty quick or I have become patient with it as I learned how the fediverse works.