It really depends when asking that question.
People who like single player will obviously lean to Zipper's SOCOM, but Confrontation's online may be better since the game is focused on that entirely.
Like I said, I hope Zipper can make an all round great game so people don't have to pick and choose between the 2.
Personally, I think Confrontation will be better. The idea of creating a custom character (similar to R6V) makes me feel warm inside.