What can I say; it was surprisingly good.
Anyway, I really liked this game. The graphics are pretty darn good for an RTS; some of the best I've seen, in fact. The only disappointing factors of the graphics are the water detail and environment textures, but that's to be expected in a game of such scale as an RTS. The explosions and effects are very aesthetically pleasing, and the added heat distortion effect makes the explosions quite good. The sounds aren't quite as good as the visuals, but the background music is fitting, and the heavy metal theme that turns on during battles is pretty cool.
Because I've only played the demo, I've only experienced the Hierarchy, but the sheer amount of customization available to them basically defines how the rest of the game will look, and other reviewers who have played the whole game agree. It was very satisfying to deck out a giant walker with plasma turrets and just stomp all over everything while producing Grunts on the fly to do away with straggling Novus bots and insignificant human fools.
That's another great aspect of the game: the insignificant human fools. It's lots of fun to just demolish entire regiments of them and dozens of their most heavily armored tanks with just a handful or two of guys. It's also fun to possess them and turn them on their allies, while harvesting their souls for resources at the same time (at least, that's what it looked like when I turned a Hierarchy gatherer on some troops).
Because I generally dislike RTS games, I was surprised that I really liked this one. The bottom line: if you like RTS, you will like this game. If you like Starcraft, you will like this game. Even if you don't like RTS, at least give this one a try (as long as you enjoy aliens blowing up everything mankind has worked thousands of years to create).