You want to choose between Wii U, Ps3 and Pc? Its simple, you are buying a console for Call of Duty but also want motion control. Wii u third party support sucks ass so i wouldn't buy the Wii u for CoD. The first party games ( mario,.. ) are coming next year so don't worry about that. A gaming pc is expensive if you don't know how it works. You need to buy parts and if you buy one pre made it will cost you more. Call of Duty on ps3 is always shitty but now after some patches its playable. Ask this for yourself:
Do you want a gaming console primary for CoD online? yes -- Xbox 360
Are you interested in collecting trophy's and stuff in-game? yes -- Ps3 / Xbox 360
Do you want to pay for online? Yes -- Xbox 360 ( No : Ps3, Wii u, Pc )
Do you buy your games digital? Yes -- PC.
Are you fan of Zelda, Mario and stuff? Yes -- Wii U
Do you want a complete new way of gaming? Yes -- Wii U
Are graphics important for you? Yes -- PC
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I own a Ps3 btw.