Just got this a while ago...
Absolutely the most beautiful game, ever. I've seen scenes in the game cooler-looking than any render I've ever done, and then some. Reflection, particles (and more particles), stunningly detailed models... and if the actual strategy's a bit weak, and the gameplay a bit confusing due to the excess of detail, who's to notice?
The screenies don't do it justice, particularly since I took 'em before I cranked it up to full resolution. I recommend getting this game just to drool over the graphics.
As for the actual gameplay, better than most. Basically, if you liked Master of Orion, you'll like this, but you'll be quick to note that it doesn't quite come up to its ancestor. The diplomacy is restricted to multiplayer (which I can't get working, damn Gamespy), and the fighting, well, I've seen better. Somewhere between StarCraft and HomeWorld, with bonus points for overcomplexity (you really can overextend yourself in this game, get spread across a dozen or so star systems, at least in the more advanced bits. It's fun.)
So, anyway. That's my impromptu review. Want pretty pictures, get this, definitely and now. I'd recommend getting this anyway, most cases, but MOO3 is coming soon, and it promises to be truly godly, if the hints they're dropping are true...