I don't see why people are up in arms about which one is going to sell more. Play what you like. MW3 will sell more because it is a bigger title. I prefer BF games because they suit my style of play. I don't like DM or TDM. They bore the hell out of me. No objective other than to spaz out as fast as you can and rack up big kills and pretend what you are doing really matters in life. I'M PRO YO!
WRT Steam and Origin, it is just gamers being the babies they usually are. Gamers cried about Steam when it first started. Then they found they liked it. Now they are crying about Origin. I think Origin is fine. It is basically Steam with different colors and a smaller game library. It hasn't affect my game play one bit. People need to stop being babies and just blow stuff up with ur buddies.