I moved from Lemmy.ml because I liked the name of Lemmy.world and it ran a newer Lemmy version which meant I could make communities. I moved from Lemmy.world because they defederated from piracy communities they didn't even host (but for some reason still kept the small piracy community they DID host) From thelemmy.club because I couldn't see the Hackintosh community from there (probably defederated) Now I spent some time looking on join-lemmy.org and checked out some instances and this (lemy.lol) instance seemed good, so I chose that.
Honest question... What's the difference? I just signed up with .world without really doing much looking around first...