MrMrC, I’ve yet to experiment with the two different systems, but I feel like what you should do my depend on your game content. For instance, within closed quarters, simulating bullets doesn’t really have much practicality. You won’t gain any realism if an enemy your player is attacking is within, say 100ft, because the bullet would likely travel quicker than their ping.
Also, because small caliber bullets are, well, small, the player likely won’t even notice a projectile if you create one.
However, if you are going to assume long ranges of combat, then simulations may add some realism.
Also depending on the weapon, because the auto-hit mechanic really isn’t convincing for a grenade launcher, or those retro-scifi bows which shoot god-knows-what, or most energy weapons, like those of the Halo games.
So in other words… IMO it really depends on context.