It depends on the version of Lemmy that your instance is running. My account is on sh.itjust.works which upgraded Lemmy versions a few months ago. Apparently it changed a parameter name that keeps track if a post has been read or not.

So on Sync, you can click on posts, but they never show as read. It’s super annoying, so I went back to Voyager.

I used to use RiF and loved Sync for Lemmy too. I just wish the developer would fix the bug for posts showing unread! It’s completely stopped me from using the app for something like 6 months now.

There are a few minor cultural differences to be aware of. But as long as you avoid saying anything negative about Star Trek or Linux, you should be just fine.