What's better? (FA:S, TFA, CW 2.0 or M9K?)

If you need attachments - CW2.0 or FAS (TFA partially)
If you "I want everything at once" - M9K (for other weapon systems you need search packs (CW2.0 and FAS have stock weapons) )
TFA is most realistic weapon system in my opinion, but for attachments you need download additional addon + in CW2.0 and FAS you can manage attachments drop, but in TFA attachments drops after pick weapon