I just had both in my hands the other week. I can give you a breakdown of my impressions of both.
-The glass is definitely better on the Viper than the Strike Eagle. That being said, the glass was good on the Strike Eagle. I think the only time it may make a difference would be if you were hunting heavily wooded areas, or near dusk. If I had not had the Viper in my hand I would have thought it was great.
- The overall build of the Viper seemed batter than the Strike Eagle. Both do have the lifetime warranty though.
- I am not used to first focal plane reticles like those found on the Viper. I found the little circle not that great when on 1x. The second focal plane reticle on the Strike Eagle was the same size through all power settings. Personally, I did not see the point of it in such a low powered scope.
- I liked the semi circle with the partial cross hairs inside found on the Strike Eagle. It allows quick target acquisition at close range, but allows the cross hairs to be used at distance. That was a big thing for me as I wanted it for testing loads at 100 yards (my Millett DMS-1 did not work as well for that).
- The extra zoom of the Strike Eagle I found a major benefit when looking through both at distance.
- The Viper was about $300 more expensive than the Strike Eagle where I was looking.
After all of that, I went with the Strike Eagle. I am using it on a non critical rifle so I am not worried about failures. If I was trusting my life to one of them, I probably would have gone with the Viper, but how many of us actually need a scope for that anyway? The cost difference was a big thing too; I am forking out more in daycare bills than my mortgage right now, so cost is a factor.