I have a Sightron SII in 3X9X42. I believe it is an excellent scope - great optics and passes all the "scope tests" (shooting the box, same POI through all powers, etc) with flying colors. I do not freeze my scopes and then put them in boiling water or things like that! I also own Burris FFII's, Nikon Buckmaster and Monarch, Bushnell 3200's and 4200's, some Leupold M8 fixed powers, and many other Redfields, Bausch & Lombs, Muelllers, and less expensive scopes. All I can tell you is I feel the Sightron is as good as any of my other scopes. They also have a great warranty. I would sure buy another. I have no experience with the SI's or III's. There really are a lot of great scopes and scope values on the market nowadays IMO. For hunting, I have mostly been using the Bushnell 4200's because I think they are excellent in every way (eye relief works fine for me, although some feel they are short) and the Rainguard feature clinches the deal for me.