IRL The FAMAS is a more versatile and reliable gun. An even bigger plus is the fact that it has the ability to switch between 3 Round burst and Fully automatic in one system instead of different models like the M16 (A1, A2, Etc)
Famas has a slower damage drop off than the M16. Meaning you have a better chance of 1 bursting a guy who's far away compared to the M16 depending on the range. M16 becomes more accurate than Famas when you put holographic sight on it. But i still prefer famas. looks sexier.
I prefer the Famas over the M16 because of how fast it shoots, damage, and recoil.
Though I did read on the fact that the M16 with a Holographic Sight decreases recoil so it's basically on par with the Famas.
I still prefer the Famas