First of all, the two games have super different play styles and communities. SOCOM players are incredibly talkative, teamwork oriented, and enjoy some serious fun. CoD - When I played Modern Warfare and World at War, almost nobody talked, and there was no tactics involved, run and gun basically.
I don't like CoD anymore, and I don't really care to much for blindly running and gunning. I love games where you get to be very tactical with a community that is there to do the same.
Oh, and SOCOM Confrontation sucked because the studio that made the PSP versions made it. The original developer for the PS2 iterations, Zipper Interactive (M.A.G.), are making SOCOM 4.