I recently got Supreme Commander and have proven, several times, that despite meeting the minimum requires, my computer really can't play the game. (Among other things, it's crashed half the time I've tried to play it, and one of the only games that didn't crash fell to below 1 FPS when I was attacking the enemies main base.)
So, since I can't actually play the game, I can't exactly create a review for it. Instead, I'm going to compare it to Total Annihilation, since Supreme Commander is TA's "spiritual successor."
First off, unit types. TA had four unit types: KBots, vehicles (tanks), airplanes, and ships. (This was later expanded to include hovercraft.) SC simplifies this to three: land, air, and water. While there are no units called kbots, all three factions have large walking robots (excluding the Commander, of course). So there's a smaller collection of units to contend with, and most units take on roles similar to TA: anti-air, anti-land, anti-water, anti-base, and others.