Cutter,
Cheap is like everything else, made the quickest way possible and no attention paid to detail. In scope rings, both need to be the same as close as possible. If they are off, can bend, dent, bind, tube and adjustments to ruin optic. As mention before, screws strip, break off, scratch metal, and may have to be lapped. They can also through out sight aliment. I have tested many systems as these for use by law enforcement snipers. While there are many good systems out there the junk is too. As stated before, if it works cost does not matter but cheap ones that do not have some sort of problems are rare. I have had to cut two sets of Ruger rings off optics in the past year. In both cases, screws stripped and the head actually broke off one.
A good scope base and ring system is more important than your optic in my opinion. Does not matter if you have a $1500 scope when the rings and bases don't work.