From all the gameplay footage I saw with Hawken, this game is somewhat similar to mechwarrior back in the day but with the speed of modern multiplayer games such as Call of Duty. The pace is what got me interested in the first place. This is purely an online multiplayer game, with four game modes planned so far. Hawken will be Free-To-Play when it gets officially released.
The client will be available for download on 12/12/12. As I write this, the timer shown on the upper left shows the open beta starts in 10 hours. You can create an account now in preparation.