Multiplayer mech game Hawken has finally has its NDA lifted, which means a load of beta footage for you. Below are a couple of video compilations I've come across, which feature some promising looking mechanized action, complete with reasonably strong graphics and audio.
Word is the game is the 'twitchy' counterpart to MechWarrior Online, so if you prefer a faster pace, this may be the one for you. Also of note: according to PC Gamer, skill is rewarded more heavily than what customizations you buy, so this won't be 'pay to win' like some other free to play games.
If you haven't yet signed up for beta, hit the source.