As I've said, it varies. They copied the Adco E-Dot, which is a very good, very reliable red dot that costs $100-$120. The unit they copied it from was solid, but their quality control isn't the best. Sometimes you get a good one, sometimes you get a bad one.
If you want a lot of bang for your buck, go Adco. They have a 3 MOA 30mm red dot at $150. I think the $120 E-Dot is 5 MOA. Their warranty is good, too. I've abused the hell out of my old E-Dot, and it still works as good as the day I bought it.