Never ever compare free to play to paid to play.
You will know an obvious difference.
But Cod is harder to run because of it's awesome graphics so you will need good graphics card or it won't work since it's better.
A good computer that don't lag..... not like a bitch /
Depends if you have on your computer. If you're computer isn't that good, COD will lag a lot more than CA.
CA only has multiplayer whilst COD has single as well as multiplayer. It's really up to you, COD is general a good quality game.