I too have both sfp and ffp.
To me, the biggest difference is if you plan to use marks on the reticle or not. On a second focal plane, most scopes require the scope to be at, or near, full magnification in order for the marks to be correct. I have a Swarovski Z5 5x25x52 that has MOA windage marks. In order for those marks to be correct, the scope has to be on 25X. If you have any kind of mirage and need to back it down, then the marks aren't correct. With a FFP, this is not the case. The marks and subtentions are the same throughout the magnification of that scope. Even with my 24X scopes on my range rifles, I usually keep them between 18-20X if I'm having to lower for mirage. As was also stated, if you and a partner both have similar set ups (mil/mil, moa/moa) then you can use the reticle and help with shots made or missed and use the reticle for measuring throughout the mag range.
So I'm pretty much like Tugboater and use SFP for most of my hunting and FFP for steel banging. I do however, have a March FFP scope that the reticle post are tapered and quite large when on lower mag ranges and it is not a bad hunting scope. But for a lot of scopes, the reticle on low mag ranges for FFP is hard to see.