So again, many of these things are personal taste. I enjoy gaming on the PC, I enjoy a more team-based, strategy-oriented experience with vehicles and distinct roles that all feel different to play, and dedicated servers with high player counts are attractive. One of these war games will deliver what I like in action games, and the other is Modern Warfare 3.
It's unlikely that EA will ever outsell Activision in this area, but popularity doesn't equal quality. I'll buy both games, but six months after launch I'll likely only be playing one of them. I'll let you guess which one.