I have two sets of them, and for the same reasons you just described. Yes, I was unsure myself with them, until I got them.
They say made in USA, I am not sure, as the packaging is that cheap thin cardboard I only see from across the Pacific. All the measurements on their site is metric, so I would asume they are. I could be wrong though. Anyway, first impression of them was very nice machining, and put together well. They are wide rings, not the normal I see from most manufactures. The top half ring screws, heavy duty, and not small by any means. All the corners are beveled edges. Nice machine work has been done on them.
It has a spring loaded torx tensioner screw for the rail. I prefer the hex nut style, but work just fine anyway. For the scope you are wanting to mount, the medium height rings is perfect for a 50 mm objective, just enough clearance on a AR flat base which is what I prefer. I have looked around at a lot of manufactures with ring height for a 50 mm objective. Very few have the perfect height for one without having to use something to raise you cheek height and getting some air. Some do but cost is up there. I think the UTG medium height is at 1.250". You might even get away with a 56 mm objective with them on a AR based flat rail.
So, I got them for $40 on sale, worth it for me. They are still on my rifles, work just like intended, no issues, hold precise shots, have yet to loosen up, and leave no ring marks. I like them, will not hesitate to buy more.