I think they are well made and good quality.
I also think they look nice and sleek, and believe they work well up to a point.
I had a 602 Brno .375H&H Mag with Conetrol mounts and a 1.5 to 5 Leupold, and I could never stop scope slippage.
Took them off that rifle and put them on an early BSA .308, and they worked fine.