It's very good! I've been using it all day, and quite honestly, it has ignited my excitement for Lemmy.
I paid for the year license just to applaud the dev for a job well done. I'll obviously use it a lot over the year, but, I think on the Fedi it's important to share the love.
I had been alternating between a few different apps, and none of them really felt quite as smooth as Sync did. The fact that it works so well out of the box is awesome!