Tons of content and hours of enjoyment
Empire Earth has a huge amount of content. There are about 15 differant playable cultures which you can command through 15 ages of the earth, from prehistoric, to medieval, to renaissance, and even past modern times and into futuristic epocs. While the differant cultures all share a set of common units and structures, there is enough variation between the factions to clearly define one culture from another.
This game is all about setting up a base, having your villiagers mine minerals, chop wood and hunt, and cranking out tons of combat units which you will use to destroy your enemies. While this is not an original formula, empire earth puts it all together in a way that just makes it alot more fun than many RTS games out there.
You will command HUGE armies accross HUGE maps, and its a nice change of favor from alot of the modern RTS titles which focus on strategic points rather than amassing armies. But that's not to say that strategy is not important.
Graphically it's nothing special, however in 2001 it was nice to look at.
If you're looking for some solid bargain-bin RTS gameplay, this is the game you want.