I just checked the servos I hadn't yet used (and have not had a chance to backdrive them...) - both have considerable slack straight from new.
Doesn't affect my machine too much, but I wouldn't put this into anything flying or driving.
Overshoot and jerkiness seem (very unscientifically) not worse than other servos in that price bracket.
I use them with up to 60cm of extension and and they stay steady, but I only operate the machine within a few meters,
so this won't be illustrative for most other uses.