Hmm I've never used the hiwonder servos so I'm not sure how they compare with the feetech/waveshare STS type, but these have been surprisignly good overall. There is still considerable backlash which results in a cumulative 1-2cm of gripper translational error when accumulated along the arm, but the control is really stable. I don't think there's any jitter at all. They are a bit loud when moving at max speed, but there is also a STS3250 brushless variant that's stronger and really quiet. Expensive though.

I haven't tested the Lekivi specifically, but lots of SO-ARMs and a custom built lekivi-like robot. I think some people have had some issues with the rear omni wheel when moving forward but I haven't seen that myself.