If you don't range with your scope, FFP is useless...
As a long-range shooter at minute-of-angle size targets at KNOWN distances, I also find FFP scopes useless as the reticle covers my target at high magnification.
If you're a hunter, or long-range shooter where targets are at UNKNOWN range, then FFP may be for you.
That's it in a nutshell, but here's Vortex Optics explaining it in a video:
http://www.vortexoptics.com/video/fi...nd_focal_plane