I did a poll and nearly 30% of the people who voted said they used Sync! It's stayed around that percent the whole time too!
EDIT: Here is the poll I forgot to put this here like five times lol https://strawpoll.com/wby5A21R1yA
Yes this is my main complaint too with Jerboa, scrolling just feels sluggy, I tried to look into the issue/source-code, but couldn't find the source of it. When Sync came out, everything was buttery smooth and I was sold (though I'm not the biggest fan of the interface, maybe I'll switch to an open-source client again, when there's a more robust less sluggish client again).