Which is better Halo or Duty?

Halo 1, 2, and 3 are all very good games made by Bungie and Microsoft and is only made for the Xbox. Call of Duty 1, 2, 3, 4,and 5 are also very good, but they didn't start getting popular until the third game. The Call of Duty games are for all systems which is another positive thing. Halo 1, 2, and 3 are shooting games based on "super soldiers" that are created to fight aliens. Call of Duty on the other hand are shooting games where you are just an ordinary soldier in different time periods in each game. I personally think halo is way better because it is less complicated and more fun. please give your opinion unless you havenever played either one.