FCNPC sucks, mainly because it's modifying the memory and other shitz thus it's unreliable. There wasn't any update for a long time after 0.3z R2 was released, now it's finally updated but I see that people are having problems with it. Some servers needed to use the older version of 0.3z thus they were vulnerable to these lagger shit attacks.
I have a pretty much advanced zombie script using RNPC plugin (but I had problems with using the default MapAndreas which is included into it, so I'm using normal MapAndreas) and I've also wanted to use FCNPC but now I don't regret my decision, I needed to create some functions on my own but that wasn't really a problem.