I've gone through a few of the small harbor freight tumblers. I have a nice expensive one as well, but the harbor freight is actually quicker to clean parts. The problem with the harbor freight seems to be how fast it vibrates and its off balance. It often vibrates its self apart causing the lid to shake and wing-nut eventually to fall off.
My first one failed, and had the same issues show in someones post above. I double nut close the unit and have not had issue since.
People often overload the unit, also causing excessive balance and wear issues.
They used to put them on sale, and you could buy an extend warranty for very little. They replaced my first unit for free. My last unit I have had for 5 years without issue.

My small HF will actually clean the parts quicker than my high dollar unit. Dont get me wrong the HF is bottom of the barrel but it works. If your doing 1-2 machines, then get the HF and double nut it. If you plan to do more, than buy a quality unit.....

My high end dollar unit is: https://rocktumbler.com/thumlers/model-uv10.shtml. It's slower, but a much better made unit. HF sell walnut media cheap. Been using that for years with a little metal polish or Brasco.

Bingo. I only buy quality tools, and typically stay away from HF. But the flip side, if I am going to only use something once or not sure its something I will reuse HF fits the bill. If I don't use it again, or it fails its usually trivial $$$.

If your thinking this hard about it, then buy the quality one. I bought the HF, and then moved onto a nice one. I got the HF for $49, and my nice one was over $300.

I own the same one. Expensive but built like a tank. But takes longer than other units to polish.