I certainly wouldnt describe MTC scopes as being "cheap",unless you are able to afford four figure price tags ! My Viper does not have a problem when the light levels start to go, well, no more than any other scope I have ever owned or been able to afford.
Overall, I think this particular brand represents excellent value for money. I can also personally vouch for the first class customer service from MTC. What more could you ask for ?
Andy