In researching my recent purchase of a SIII 6-24x50 with MOA-2 reticle, I had the same questions. The only advantage I could see with the FFP is was were you needed the ability to quickly range, aquire and shoot various targets from close to far without the aid of a rangefinder. The Mil or MOA substensions stay the same at any power setting making the hold overs you had memorized straight forward, expecially in a timed match. Because I usually have a digital range finder and dope chart available when varmint hunting, I really don't want to spend a lot of time looking through a scope trying to estimate ranges. I can till still do so if need with the SFP at 24X (2-MOA) or 12X (4-MOA) if mirage is getting bad. And if I miss a Pdog, I adjust over to the dot/hash-mark where the bullet hit and shoot again. Most bench shooters also claimed they prefered the SPF over the FFP because the reticle did not grow as you increased power to cover the center ring at long distances. Once I determined I really did not need a FFP scope and some of the extra features offered on the Vortex PST, I went with the SIII which cost less than the Vortex PST.