I have both, and like both for different missions. I have Nightforce NXS 5.5-25x56 SFP's for my hunting rifles and Nightforce ATACR 7-35x56 FFP's for my "battle rifles". I generally like to dial my long range shots and not do a hold over when hunting, so I like a constant size crosshairs whether I'm shooting close at 50 yards at 5.5 power or 750 yards at 25 power. At low light, typical of hunting shots, I find the small FFP reticle at low power for closer shots unusable. I don't rush a shot while hunting. Too much at stake to go wrong with rushing. For my self defense or battle rifles or my extreme long range rifles I use FFP for rapid engagement at widely varying ranges. But I find I'm always at 10 or 12 power or higher to make the reticle usable. All of my reticle's are illuminated and I have great 20/10 vision. I find myself generally preferring SFP better.