If it's the plain Viper with the BDC reticle, I've got two of them. One is on my long range AR and works well for the purpose. Tracks true and holds zero perfectly. Glass is good, but not great. I routinely shoot it to 600 yards and have no complaints out to that distance.
Silver spurs and gold tequila
keep me hanging on.
Pretty girls and old cantinas
give me shelter from the storm.