I'm going to start this review by comparing it to its predecessor, Battlefield Bad Company 2. The mechanics in this game have well been thought out to create the most realistic battle experience you can imagine. Leaping over obstacles, working with your teammates, and blowing up parts of the environment has never been so awesome. The Frostbite 2.0 engine has really made this game what it is, a marvel to look at. However, what I like the most about Battlefield 3 isn't just in the visuals or the gameplay, I've fallen in love with the sound. Hearing bullets fly past your ears is nothing but adrenaline pumping, and this new sound quality far surpasses Bad Company 2.
If you want an arcade, fast paced shooter, I would purchase Modern Warfare 3. However, if you want the most realistic battle simulation available, make sure you buy Battlefield 3!