Just use the decreasing sized circles to cover the chest of your target or the area between the two nearest fitting circles and you are on target that quick when switching targets. This feature allows the marksman to engage multiple targets at various ranges quickly when switching targets.
If they can do what they claim, and are as accurate as reported, then I see no reason to own any other scope. If I have the available funds by the end of next year, I might try and outfit a rifle I'm looking into buying with one.
The ranging method they use is similar to the older Soviet "choke" style ranging scopes. PSO series use it. It has a graduated scale that subtends a 5 foot 6 inch tall man,you bracket your target in the scale,if he fills the scale without going over,he's X number meters away. The Shepard circle subtends the chest area of a given animal.
The Shepherd I put on the standard Springfield Armory pre 1989 M1A allowed the shooter to move from one range to another at light speed. That M1A would put Spanish Santa Barbara 7.62x51 Ball ammo through the same EXACT hole at 100 yards and further. I sold it to a contract agent for Uncle Sam who uses it to get special fellons. He has been offered 300 plus just for the scope and rifle.