Supreme Commander 2 is an amazing RTS with epic battles and intense multiplayer.
When you play in a skirmish, campaign, or multiplayer, you choose between three different factions: the classic human faction AKA the UEF, the robot obsessed Cybran, and the alien Illuminate. Each faction is different from the other three and is fun to play as. They each have varying units and abilities. One of the main differences between the factions (and the entire RTS itself) is the powerful experimental units. They can change the tide of the war. For example the UEF have the AC1000 Terror based off the modern day AC130 Specter. Cybran have a giant mechanical Kraken and T-Rex. The Illuminate have a giant hovering UFO also. Another Supcom2 specific feature is the strategic zoom. This allows you to zoom out far enough to see the entire map. From this view you can control many armies on multiple fronts.
Supcom2 has a nice soundtrack that changes depending on what is going on. More epic music is played during battles, whereas nothing or more soothing music is played while nothing is happening. The graphics are pretty good too, with nice detail on each of the buildings and units.
The only problem I can think of with this game is that the campaign isn't very fun and is a bit short. Other than that it's a near perfect RTS. Supcom2 is a must buy for RTS fans, and is worth trying even if you haven't tried an RTS.