The first Dawn of War was innovative to the RTS genre, bringing in elements such as morale, cover, and squad units. The first expansion: Winter Assault brought in new factions, new gameplay elements, new units, and 2 new campaigns. Now with Dark crusade, there are 7 campaigns on 1 map and it's better than you expect it to be.
In the single player campaign, there are 7 factions each with their advantages, disadvantages and significant playstyle:

Chaos
Advantages: Diverse infantry, good morale
Disadvantages: relatively expensive buildings.
Significant playstyle: Daemons to teleport, use cultists to capture points first, and using chaos magic to kill the enemy.

Eldar
Advantages: Fast, being able to teleport, becoming invisible.
Disadvantages: Weak infantry, buildings are not the most durable.
Significant playstyle: Using super destructive psykic powers and webway gates to travel quickly.

Imperial Guard
Advantages: Has commander units such as psykers, commissars, priests, arguably the best vehicle units and best relic unit; the Baneblade.
Disadvantages: Weakest infantry units, weakest morale, not effective unless in big numbers or with commander units attached or with vehicle support.
Significant playstyle: Produce as much units as possible, get vehicle units ASAP, and plenty of commanders to attach.

Necrons
Advantages: Most durable infantry, arguably best morale (yes these guys can still think they could potentially lose), has 2 relic units and could revive fallen units. Some units are free.
Disadvantages: Slowest faction in the game, only builder units can capture points, slowest to produce.
Significant Playstyle: Only 1 type of resource is used; energy.

P.S. If you are new to Dawn of War as a series, do not play Necrons first, play the other games or start with a different faction.

Orks
Advantages: Fast producing, good durability, good morale.
Disadvantages: I don't really recall any disadvan- WE DA ORKS AND WE 'AVE NO NUFFIN' BAD ABOUT US!!! KWIT TOKKIN' SMAKK ABOUT US HUMIE GIT OR WE WILL KRUMP YOU GUD!!!
SIGNIFIKANT PLAYSTYLE: WE DA ORKS AND WE 'AVE PLENTY OF BOYZ TO GO, WE BUILD WAAAGH!!! BANNERS SO WE 'AVE MORE BOYZ, AND DA 'UMIES KALL US GREENSKINZ AND WE BRING ZEM DA GREEN TIDE. WAAAAAAAAGGGGHHHH!!!!

Space marines
Advantages: Diverse weaponry, being able to counter any opponent by adding weapons to your squad. Flamers to counter melee units, plasma guns to counter heavy infantry, heavy bolter to counter numerous infantry, rocket launchers to counter vehicles and buildings.
DIsadvantages: Expensive infantry, vehicles feel weak.
Significant playstyle: Using servo skulls to detect infiltrated units because librarians are not enough. Using infantry weapons to counter what the enemy throws at you.

Tau
Advantages: Best range in the game (obviously), kroots and vespids auxilleries to make up for melee, invisiblity, awesome gunships, and powerful battlesuits.
Disadvantages: Worst melee in the game(even more obviously) No turret or landmines.
Significant playstyle: No turret or land mines. Elite tier units can either be better gunships or better kroot units.


Now the story is your typical 40k story except there are 7 factions fighting each other even the guard and space marines.
There is dialogue interaction with all the characters, the voiceovers were some of the best i heard, and the gameplay has been improved. In the campaign , there is a "meta map" like Risk, there are provinces, provinces conquered will give you either honor guard units, or special abilities such as ignoring adjacency, or being able to attack twice per turn.

The game has aged but that's OK because we can play the game on modern day computers and still run smoothly on maximum settings, the multiplayer is dying if not dead. But the single player is a blast to play, multiple endings and replay value. According to the next games in the Dawn of War series,the canon victor is Space Marines

I recommend it to everyone who played the last 2 Dawn of War, RTS players in general, and the Warhammer 40000 community as well.

The first Dawn of War was innovative to the RTS genre, bringing in elements such as morale, cover, and squad units. The first expansion: Winter Assault brought in new factions, new gameplay elements, new units, and 2 new campaigns. Now with Dark crusade, there are 7 campaigns on 1 map and it's better than you expect it to be. In the single player campaign, there are 7 factions each with their advantages, disadvantages and significant playstyle: Chaos Advantages: Diverse infantry, good morale Disadvantages: relatively expensive buildings. Significant playstyle: Daemons to teleport, use cultists to capture points first, and using chaos magic to kill the enemy. Eldar Advantages: Fast, being able to teleport, becoming invisible. Disadvantages: Weak infantry, buildings are not the most durable. Significant playstyle: Using super destructive psykic powers and webway gates to travel quickly. Imperial Guard Advantages: Has commander units such as psykers, commissars, priests, arguably the best vehicle units and best relic unit; the Baneblade. Disadvantages: Weakest infantry units, weakest morale, not effective unless in big numbers or with commander units attached or with vehicle support. Significant playstyle: Produce as much units as possible, get vehicle units ASAP, and plenty of commanders to attach. Necrons Advantages: Most durable infantry, arguably best morale (yes these guys can still think they could potentially lose), has 2 relic units and could revive fallen units. Some units are free. Disadvantages: Slowest faction in the game, only builder units can capture points, slowest to produce. Significant Playstyle: Only 1 type of resource is used; energy. P.S. If you are new to Dawn of War as a series, do not play Necrons first, play the other games or start with a different faction. Orks Advantages: Fast producing, good durability, good morale. Disadvantages: [strike] I don't really recall any disadvan- [/strike] WE DA ORKS AND WE 'AVE NO NUFFIN' BAD ABOUT US!!! KWIT TOKKIN' SMAKK ABOUT US HUMIE GIT OR WE WILL KRUMP YOU GUD!!! SIGNIFIKANT PLAYSTYLE: WE DA ORKS AND WE 'AVE PLENTY OF BOYZ TO GO, WE BUILD WAAAGH!!! BANNERS SO WE 'AVE MORE BOYZ, AND DA 'UMIES KALL US GREENSKINZ AND WE BRING ZEM DA GREEN TIDE. WAAAAAAAAGGGGHHHH!!!! Space marines Advantages: Diverse weaponry, being able to counter any opponent by adding weapons to your squad. Flamers to counter melee units, plasma guns to counter heavy infantry, heavy bolter to counter numerous infantry, rocket launchers to counter vehicles and buildings. DIsadvantages: Expensive infantry, vehicles feel weak. Significant playstyle: Using servo skulls to detect infiltrated units because librarians are not enough. Using infantry weapons to counter what the enemy throws at you. Tau Advantages: Best range in the game (obviously), kroots and vespids auxilleries to make up for melee, invisiblity, awesome gunships, and powerful battlesuits. Disadvantages: Worst melee in the game(even more obviously) No turret or landmines. Significant playstyle: No turret or land mines. Elite tier units can either be better gunships or better kroot units. Now the story is your typical 40k story except there are 7 factions fighting each other even the guard and space marines. There is dialogue interaction with all the characters, the voiceovers were some of the best i heard, and the gameplay has been improved. In the campaign , there is a "meta map" like Risk, there are provinces, provinces conquered will give you either honor guard units, or special abilities such as ignoring adjacency, or being able to attack twice per turn. The game has aged but that's OK because we can play the game on modern day computers and still run smoothly on maximum settings, the multiplayer is dying if not dead. But the single player is a blast to play, multiple endings and replay value. According to the next games in the Dawn of War series,the canon victor is [spoiler] Space Marines [/spoiler] I recommend it to everyone who played the last 2 Dawn of War, RTS players in general, and the Warhammer 40000 community as well.