In summary: Good, stable tuners that also look nice on a ukulele. Buyers should pay attention to the fit of the pre-drilled holes of their ukulele, unless they want to enlarge them themselves.
I used these tuners to replace those of my ukulele. The original ones would not stay in tune properly. I bought these to fix that. They have not let me down! I've had them for several months now. The ukulele still tunes smoothly and precisely, and remains in tune.
One of the tuners feels a bit looser than the others.
So this may differ from set to set. In my opinion this does not affect the functionality. The plastic buttons also feel like they are of a good quality.
I had to enlarge the previous holes so that the tuners would fit. In the end, of course, that was not a problem but it's something you should measure before you buy them.
They looked very nice on my ukulele. The gears give it a unique look. I would put a small drop of lubricant in between them. It seemed a bit dry, so I was afraid that it would be too rough. That's why I immediately lubricated it.