I played it a bit in beta. Ended up stopping cause trying to play online via Live sucked monkey balls at the time.
The unique units and graphics were pretty good. And it felt like you couldn't just rush as a person knowledgable about the unit types could counter a 1 unit type blitz.
With the special powers and different unlockable skills for the races it probably has a bit higher learning curve than most of the type; assuming to a degree that each race doesn't eand up having one uber path with the rest being mediocre.