COD4 Trade Situation

I picked up COD4 about 2 weeks ago for $20 new. I play it once or twice and didn't really like it. My bro has been playing it instead. I have a chance to trade for Halo 3 in same condition. What do you guys think? I've play Halo 1 and Halo 2 and enjoyed very much. THanks.

Which one is better for single campaign? I really don't play online much at all. Tx.dominicancivik

Halo 3. Longer and u can do co-op. YOU CAN DO IT!