At 100-150 yards, I like a 4x bottom power at the most. At 500 yards, I usually shoot around 10-12x (on steel). On paper at 100 yards from a bench, I also like 10x for tight groups. Lots of guys are shooting to 1000 yards on 18x even with a 25x magnification just for field of view.
As far as SFP vs FFP, the only time I find it matters at all is if I want to use the reticle for ranging and hold over. FFP is best in that scenario since you aren't locked in to one magnification where the reticle is accurate. If you plan to dial for drop, the point is largely moot. I like FFP on target scopes and SFP on hunting scopes for this purpose. With a 100 yard zero on a hunting scope, I hold for top of shoulder to 200, top of back to 250, and dial for 300+. An animal grazing at 300+ yards isn't going to vanish while I count the clicks on my dial.
If you want "the best" hunting riflescopes that will have enough FOV on the bottom, enough adjustment in the tube to dial for extended ranges, offer unreal clarity and definition, dead reliable tracking, illumination options, and easily ring steel well past 500 yards I would recommend the Vortex Razor HD LHT 3-15x42, Leupold VX-5HD 3-15x44, and Leica Amplus 6 3-18x44. All are just a bit over your budget but your level of regret will be low-to-nonexistant with any of those. I own the VX-5 and have owned the Razor, and they really are at the pinnacle of weight, optical performance, and field performance.
