Modern Warfare Mod 3 brings World in Conflict from the Cold War into the Modern Age. It also ups the ante on realism and authenticity in every role – Infantry, Armor, Support and Air, while trying our best to keep everything relatively balanced for fun and interesting gameplay.
Simply put: I love it. It not only updates the models and textures of the game to better reflect modern-era combat, but changes up many of the game mechanics involved using things like simulating FLINT missile systems and ballistics(Probably the most advanced case of which I've seen in an RTS). It breathes a lot of life into a great game with a dwindling community, and addresses many of the quirky balancing issues of the vanilla game such as helicopter death balls rolling heavy AA with impunity.
Add to that a more in-depth style of play for all roles of battle with things such as infantry-made fortifications, vehicle counter measures, and more robust flight controls for helicopters and their fire systems and you get a very well-rounded upgrade to the multiplayer of WiC. My only qualm is that while the differences in functionality between the Russians and the US are much more prominent and interesting, one side has a far steeper learning curve than the other and this can lead to awkward swings of balance in the way things like JTAC's on both sides are handled, as well as the air roles (The US air role is far more capable than the Russian counter part, for instance, while the Russian support is more complex to handle but can quickly amass Scud spam.).
Overall, the community is still in it's infancy, and the balance issues are more a consequence of players simply not understanding the mechanics fully just yet. In time, the full potential of the mod will become more apparent as more players get comfortable with both of the factions.