Some of the monstrum stuff is decent. I have a set of their caps on an lpvo, they are excellent. Some of their objective lens caps restrict the field of view. I wouldn't buy a scope from them, but if you're putting rings on a light recoiling rifle, they'll do fine.
Always get a kick out of the folks posting on forums with their Chinese made phones or Chinese made computers and tablets saying that you should never buy Chinese made stuff.