The reticle can be used for ranging in both 1st and 2nd focal planes...the reticle can be used accurately for hold over and windage in both 1st and 2nd focal plane scopes. But the only disadvantage in 2nd focal plane is you MUST be on the scopes highest power. The disadvantage to first focal plane when your old you can't see the tiny reticle that changes size when you go down to the lowest power. First focal plane a huge disadvantage for fast close shots in cover where you are most likely to encounter game or your enemy in combat. I have own both, first focal plane on the toys, second focal plane on game or combat. Used a Leulold 3-10X Mark 4 M3 mill dot only 2nd focal plane for 17,000 of match 308 hit eggs and pop cans at 1000 yards, 25 years ago when I was young. Dialed the whole time use hold off on close misses... at 10X you're the same as a 1st focal plane scope. But you can still range at 3X or 5 X the space is just twice or 3 times the mils. And you can kill up close, like running squirrels, or a real threat will most always be up close, a low power variable 2nd focal plane can take care of that, plus your long range work, in reasonable fashion.
My vote for my all round use is a lower power 2nd focal plane. Target shooting a different story, the big clunky, heavy, 1st focal plane Vortex Razor's 4.5-27X I have on my long range toys, are good for shooting small groups. The world's best sniper used open sights, with over 600 kills...Marine sniper Hathcocks longest kill 2500 yds 8 power. Me, eggs at 1000 with 10X 2nd focal plane. The cross fine center hairs cover up the egg, ya gotta click up or down to see it behind the vertical cross hair then hold off... lots of actual shooting experience is probably more important than equipment ...just my experience. Use what ya like, but shoot what ya like...I do.