Good base game, mediocre campaign, great multiplayer
The high point of this game is the scale. I don't know of any other strategy games that simulate strategy on this scale. Most strategy games simulate either micromanagement (which this game does have) on a small scale, or focus on unit tactics. In a round, this game will have you commanding armies with a very intuitive UI from a tactical overlay. This is really the main appeal, don't expect a warcraft-esque upgrade system.
There are a few fundamental problems also. The game takes a while to start moving (around 30-45 minutes), and everything leading up to that point is extremely formulaic. (Start out with 3 mass extractors, 2 power plants, then a ground factory.. etc.) The game does really shine, as previously mentioned, when you have a steady income and high unit production. Then you can focus on the battle, which is very rewarding.
The game ships with a large amount of maps, and a lackluster campaign. The three factions have minimal plot and are very generic. Every mission basically plays out like a skirmish map, which doesn't provide much incentive to play the campaign. Also, the factions don't play any different. They have practically the same units, except for the experimental units. However, each does have a very unique visual style which does add some spice to the game.
The game looks amazing. While the technology isn't ground breaking, the amount of units fighting simultaneously and density of the effects really make this game look amazing. It really has to be seen in action to believe, and these scenes remind me alot of the climactic battle scenes in the new star wars movies. On the downside, this game is very taxing on any current system. I play with an AMD X2 4200+, 2 GB RAM, and a 7900GT (all OC'ed about 10-20%), and I have performance issues. The game is very stable, and has not crashed on me ever. Once a massive amount of units are in play, the game can start to really lag up. On any given round, I start with 100-ish fps, but after about an hour I get as low as 20 sometimes (at high presets). There are some settings like LOD that will give u significant performance boosts with minimal visual hit, so you can always get the game to play decently if you are willing to sacrifice some visuals.
The sounds are good, but not great. No complaints on the sound effects department. Everything sounds powerful and sharp. The music is good, but very repetitive. There must be only 5 or so tracks and they do really get very annoying. To their credit however, they are good and do suit the mood really well.
All in all, this game is very good. I recommend it to almost anyone who has an even mild interest in rts games and also the hardware to run this. The thing that makes this game stand out, more than anything, is the scale. If this sounds intruiging, go for it.