i do not own the 50s anymore but remember the AF well....i always shot sonys along side with the fuji and for me the best way to shoot with the fuji was to go back a few years, lock on the point and shoot....continuous AF is pointless, face AF ok, eye AF not...single AF is great....IMO face and (even more so) eye AF really needs continuous AF because the distance constantly changes....face might be ok, but eye just does not work...I honestly don't really know why eye and face AF are even an option with the 50s.....it is an amazing camera, truly great files but when your work demands face and especially eye AF, there are just much better options out there....with very, very close IQ they will nail every shot, even at 1.4.....
i am pretty sure the 100s will be a huge step up and will bring meaningful eye af, but sony will still have a better solution, the question then will be if you need to nail eye AF at 1.4 with someone running at you or if the fuji will be good enough for normal movement but provide the better file.....
i heard somewhere that the 50r has slightly better AF (then the 50s), i seriously doubt it, i found the AF speed difference between the lenses actually pretty strange....out of the 45, 60, 120 and 32-64, the zoom was a clear winner for me in terms of AF speed....continuous AF still not useable but clearly faster then the primes....