The Razors are the better unit, but the Viper HD is no slouch, for the price they would be very hard to beat in the optics world. The above mentioned comments are not really noticeable between the two, it would take a hunter going back & forth between them for quite some time to see any real world difference. Both units weigh the same. The low light capability is what really separates these two units, the Viper HD does very well but the Razors will buy you 8-10 minutes of better/clearer viewing from my testings. Either pair will not let you down, if monies are not an issue the Razors would be my choice & they are what I do use.
ElkNut1