I just mounted this for a customer so decided to test it against a Leupold VX
in the same power and objective lens size. Here is what we found. The eye relief was 3/8" less than the Leupold. The FOV at 3X was noticably larger with the S1 at 6X it was slightly more and at 9X they were identical. The turet adjustments on the S1 nice crisp indents very postive and leave the old friction type with the coin slot on the Leupold scope for dead. The power adjustment radius is alot shorter on the Leupold scope but even though it has a greater arc to travel to reach the power selected the Sightron S1 is much smoother. As it got dark the S1 held up to the VX1 without any problems just as bright and as they both ran out of gas I could see no real difference worth noting. So in the end the S1 was equal to the Leupold in always except the ER. It has better FOV thru most of the power band and has a better turret system. One note is that the German #4 reticule looks normal in the advertising pictures it is NOT nearly as heavy as the one in my Zeiss Conquest, it is really only roughly twice as thick as just a normal duplex. So is summary this scope is a VX1 optically for around a hundred bucks less money!!! Buy it and you wont be sorry.
Pros: Outstanding quality
Cons: NONE
This review was written in the old system and had content requirements that are different than reviews written today.