As far as quality of the materials, this is 5 stars. Powder coated steel tubing, that's all you need to know.
Because of the way its built, the monitors will sag. There's just no way around it.
There is a C bracket used to attach the horizontal portion where the monitors are mounted to the vertical one, and although there are a couple of different sets of holes there, none was enough to account for the sagging my monitors produced.
For me, I had to measure the amount of sag, which was 2", and use that to drill a separate set of holes for mounting it at an angle to account for the sag, and got it to be perfectly leveled.
Because its ( I don't recall exactly, maybe 18 ga steel?) this is not an issue for the bracket.
There could be improvement here with extra sets of holes, or, perhaps a way to level the plate that mounts to the back of the monitor, to account for the sag, which cannot be done by the way the mount is designed to hook to the horizontal bars (it's an oval cut).
I also hat to cut the plate mentioned above because it covered where the cable connected on my monitor, but that has nothing to do with the product itself, just an fyi.
Would definitely recommend and buy again!