I had a blast with this game on the PC. The story is cheez and nothing AT ALL like Front Mission 5, but in its own right, Evolved is a very fun little game. Think of it as mech candy - it's sugary, sweet fun with little depth.
Not all reviews were bad, by the way. Off the top of my head, I know GameInforner and PC Gamer both gave it high 7s - which to me means a flawed but fun gem. A lot of people had sticks up their butts when they reviewed the game for some reason.
I bought it day one because I am a big FM fan, but for $19 it's surely worth it.