Factions

You'll probably discover a lot of the nuances of the different factions in Tiberium Wars as you play the game, but here's a basic rundown on the differences between the three factions.

GDI

GDI is the baseline faction here, without any stunning abilities or notable weaknesses. Its units are powerful, but slow, making it difficult for them to react to new threats, but when leading a charge into an enemy base, they're tough to stop.

Infantry: Generally speaking, GDI's units are a bit more expensive than those of other factions, or have other drawbacks that make them difficult to use. Their infantry is arguably the best in the game, with an excellent commando and superb, if expensive, Zone Troopers to help guard against both infantry and vehicular attacks. Their normal riflemen squads are also excellent, especially since they have the Dig In power, which lets them create bunkers on the battlefield, for free, which protect them from the assaults of most other infantry and vehicles. Handy for setting up defensive positions if you know the direction from which enemies will arrive. Keep in mind that you can make a bunker, then tell the riflemen to get out and make another one, as often as you like. That will let you pop in other infantry, such as rocket squads or snipers, into the bunkers that get left behind.

A horde of Mammoths will be difficult for any enemy to deal with.

Vehicles: So far as vehicles go, the GDI are among the most powerful factions in the game, with an excellent (although, again, expensive) baseline tank in the Predator, and a very nice Mammoth tank that will be a great finishing weapon when you head into an enemy base. The Mammoth is slow, but is quite powerful, especially when upgraded with a railgun, and is the only oversized ground unit in the game (counting the Juggernaut, Tripod, and Avatar as well) that can defend itself against air units, since it has rocket pods. (The Avatar can upgrade itself with rockets as well, but this is a laborious procedure in the best of times, and expensive to boot.)

The Juggernaut unit has perhaps the farthest range of any ground-based unit in the game, and can take a beating, but can be easily destroyed by opposing commandos and is only at his best when paired with a sniper team that can get close to the enemy and spot for it.

Aerial Units: GDI is somewhat weak aerially, with very fragile air bases support either Orca gunships or Firehawk jets. Each air base will have four slots for airplanes, each of which can either house an Orca or a Firehawk, but not both. The Orcas are decent at disrupting enemy advances, but will be quickly shot down by enemy forces if they get caught by an anti-air turret or ground unit. They also suffer from limited ammunition, which forces them to often return to the airbase to be resupplied.

Firehawks are a bit better off, as they're able to switch between air-to-air missiles and surface bombs when docked at an airbase. They're a bit more vulnerable than, say, the Nod Vertigo is, since they don’t have any kind of stealth capabilities. When used as a bomber, they can also sometimes have low survivability, thanks to the fact that they drop two bombs. Sometimes, if the first ship in a group destroys their target, the other ships will whirl around looking for other targets to bomb, which can lead to them getting chewed up by defenses. Still, don't discount them. The air-to-air missiles are especially useful against the Scrin.

Structures: Although we can't justify this empirically, it feels like GDI's base defenses are slightly weaker than those of the other races. They often seem to focus on rate of fire instead of burst damage, though, so it's possible that the damage put out is equal over a given period of time.

Brotherhood of Nod

The Brotherhood of Nod is used to sticking to the shadows; it's had to do so for a long time to avoid the glare of the GDI. Now that they're ready to burst back onto the world, they're building up a new army with new strengths and weaknesses.

Nod forces are typically going to be a tad weaker than those of other factions, but will often be cheaper and quicker when moving around. Stealth is also an important factor of the Nod tactical plan, as they're capable of hiding an entire base with just a couple of structures, and many of their units (Shadow Teams, the commando, stealth tanks, etc.) have built-in stealthing capabilities. They'll arguably take more skill to work with in multiplayer, but we'll let the game theorists puzzle over that one.

Fanatics are great at dealing with unprotected buildings or low-level enemies.

Infantry: The early infantry units here are of fairly poor quality, with the militia squads being probably the worst unit in the game, but in this case you get what you pay for. You can eventually build fanatics, which are expensive, but which can quickly brunt an enemy assault that's coming your way. Fanatics are useful in the open, but assaulting a well-designed enemy base is another matter, since they'll often be taken out by defenses before they can get close enough to do real damage.

In the hands of a skilled player, the Shadow Teams will be interesting to watch, as they're capable of gliding over the battlefield and landing behind enemy lines to bomb their structures. They're undone by stealth-detecting turrets and units, but will be murderous when used against unsuspecting players.