I own a 6.5-20x50 viper vortex. I really liked the optics (other than at full power), but seemed clear and bright. Problem, I have now had two of them that won't hold zero( 8 months apart). Me and the gun smith tried everything to get good grouping with my 26" barreled AR-15 (5-6" at 100 yds)...... but everything seemed to fail. SO, two days ago we threw a Nikon Monarch on, (for testing) and now I have 1/2 " grouping at 100 yds, and 1 - 1 1/4 at 200 yds.
Customer service from them was great, exchanged the scope with very few questions ...... but I think they may have some quality control issues.