The Viper is well below a Lightstream in optical quality. It's not bad but it's not premier league. The controls are also stiff enough to give Big Nikko users a hard time. The Vipers I've seen have all been a little short in the DOF too IMO. To be fair they aren't in the same price bracket as a Lightstream either though. Perhaps there is variation in the quality of both scopes. I know the Lightstream is made in VERY small batches and I suspect the Viper is too. I doubt that that is an aid to consistent quality.