As someone who has been using sync for reddit for years, the app has come a long way and learned a lot over that time, and pretty much all of that is transferred over to the Sync for Lemmy app. The sync for Lemmy app really has a huge head start thanks to the Sync for Reddit app.
I remember when Reddit was releasing their app, they appeared to base it on Sync, and you can still see a lot of that influence today. I remember the Sync dev thinking it was all over for his app, since Reddit is copying his design and surely has a team that can develop a good app, but obviously Reddit stole a good design and ruined it.