Lowlight has a good point regarding the ranging... and with modern range finders, it's just easier to use one of them.
...besides, how many shooters honestly understand how to work backwards from target size -> range distance -> elevation... and then actually do so.
You can chose either FFP or SFP, and it depends on your style of shooting.
If you always dial everything (Elev & Wind), then SFP makes sense, as you get a nice thin reticle at all magnifications... and you can basically chose whatever reticle that you feel like (even simple cross-hairs), as it won't really matter.
If you hold over in any way (even if you dial Elev, and hold Wind), you're going to need a reticle that has some sort of calibrated unit of measurement therein (MilDot, MilHash,etc) in order to best estimate how much to hold over by. This is where FFP scopes are better than SFP scopes, as that unit of measure is relative to the target. It is 'possible' to work this out with SFP scopes, it just requires maths for each magnification (which can be a pain)... so FFP is a lot easier.
As others have mentioned, it does help with second shot follow ups, as you can (presuming a you're a good shot) measure how much you were 'off' by and readjust there afterwards for any following shots. You can even rework your wind value backwards and apply to targets at different ranges in the same direction.
So FFP becomes another tool in your toolbox for shooting at Long Range... which you can choose to use or not use. There are also many new types of complicated FFP reticles out there (Horus H59 & TReMoR2, Leupold CMR-W, etc), and each has been designed with an application in mind. You need to work out if they are applicable to what you want to use your rifle for. In addition you're going to need to spend quite a bit of time understanding how the reticle works... if not, then rather go simple MilDot or MilHash.
FFP scopes however, do have some drawbacks, in that if you are at maximum magnification the reticle can seem quite 'thick' even to the point of obscuring what you're shooting at if it's very very small.... and at minimum magnification the reticle can get so feint and small that it's hard to see. This is generally more of a problem with scopes that have a wide range of magnification.
A lot of this is scope dependant, so go look at the scope you want to buy, not just order it online, or by hearsay.
The one rule of thumb that you should follow if you use a reticle that has a unit of measurement (even with SFP), is that the turret unit of measure MUST be the same unit of measure as the reticle... if not, you're going to have to be a math genius to work stuff out on the fly. Which is just plain not fun.
Note: I'm not a hunter, and I'm more interested in 1st shot on target, given 40-60 seconds to work out: range, wind, then a firing solution, then set the scope up (turrets, parallax, hold), and then take the shot. Does this work for hunting; don't ask me, I wouldn't know.
Lastly: Spend as much on your scope as you did on your rifle... as there is no point in buying a rifle that holds better accuracy than your scope, and neither the other way round. The system is only as good as it's worst component.