AVA If you can get it to work on your PC (Very temperamental about PC specifications and compatibility).
Great eye candy and weapon options but lousy ballistics and a forum full of arrogant pricks.
The sniper rifles are way over powered, with little disadvantage. Save up for a TPG1 and be a one shot wonder over long range, medium range and short range.
Despite the problems, it is free and a blast to play every now and then.