I bought these a year ago when they were actually marketed as Vortex Sidewinders. When I received them, there was a large piece of carbon in one lens that obstructed the view. I called OP and they took care of it by sending me a new set, however, I think I would have had faster service by going through Vortex direct for the warranty service.
If they haven't changed, the front and aft lens covers don't stay put at all, which is a minor annoyance when trudging through brush, as I do while bow-hunting.
The twist up eye cups work nicely as do the focus knobs. The ergonomics are top notch in design and the rubber coating is high end.
As for the most important part, the optics, they are very good to excellent, but not superb. For the money, I don't think you can beat it. They are equal to, and maybe slightly better than say Nikon Monarchs, but not as good as the big 3 (Swaro, Leica, Zeiss). They perform well in low light, the image is clear overall, and eye strain is almost zero. In particular, the detail you can see is impressive; a testament to their light transmission to the eye. There is, however, a slight amount of fuzziness at the very edge of the view.
Overall, with the excellent warranty, these are tough to beat. That is, as long as Vortex remains a viable company able to honor it. They have a very good following with "blue collar" hunters already, but the wealthier "grand slam" hunters still cling to their big 3.
Pros: Features, Warranty, Cost