to me its
MGS2
MGS4
MGS3
MGS
3 had too much self-management (healing, changing camos, eating, etc.) & in hindsight I didnt like how 1 had a fixed camera angle which made it tougher in comparison to the recent ones.
COD4 was good when it first came out, but it got boring after awhile. I never got into multiplayer since I was coming from Battlefield & it seems like whatever FPS you're accustomed to, you'll never like any other franchise. Halo fanboys like to stick to their controls, Quake, Unreal, etc....its all different so people will complain how it aint like their favorite.
Production wise there's no match, but you could point out if MGS4 was either a video game or a low budgeted CGI film since the hours of cutscenes outnumbered the actual gameplay.