I have the m-223 20MOA mount it seems pretty soild to me. It is split in the middle on the "claws" that clamp to the rail so it was interesting, but seems to work well. They are so well priced I really questioned how good it could be, but it seems to be of good quality
I can't tell if it is holding POA that well because every other time I go to the range I am using different ammo, but ammo supplies seem to be improving so I might be able to get a better judgement of it then.
As for the scope I don't have experience with them.