Purchasing the game

[aznpwnstar]

Hi, just enjoyed playing the demo for MoW:AS and was thinking about purchasing the game. However I had a few questions about the multiplayer. Which MoW of the series has the most populated servers? i.e. less wait time for games. And are the multiplayer Map packs a necessary purchase with that? I more than likely will not be jumping into multiplayer for a good while, but once I'm more familiarized I definitely will. So any input would be appreciated. Thanks.