When Blizzard rolled out the WoTLK extension to World of Warcraft back in November 2008, a new character class was introduced known as the Death Knight. The Death Knight is unique in the fact that they are the only hero class in World of Warcraft. To be honest the fact that they were categorized under a unique class doesn't make them much more different from other similar classes.
There's also another twist to the Death Knight and that is that the character can't be unlocked until a player reaches level 55. Only then can they assume the identity of the Death Knight. When the Death Knight was introduced to WoW his purpose was that of a loyal servant to the Lich King.
Once the identity of the Death Knight class has been taken, each player begins the game with green gear, 4X12 slot bags and twenty silver in Archerus. Talent points for your Death Knight build can also be easily gained around Ebon Hold when you first play the game as the Death Knight class. It's also very possible to easily acquire blue gear for your Death Knight to boost stats fast.
Of all the classes in WoW the Warlock is my favorite, but the Death Knight comes a close second and what I can tell you is the quest chain for the Death Knight is a lot of fun and will certainly keep the player entertained. For a good leveling Death Knight leveling strategy, I would say that the Outlands are a great zone to focus your efforts and complete available quests.
The Death Knight is primarily a Melee class and possess the ability to equip there selves with most available Melee weapons found in the game. On top of this the Death Knight has the ability to equip 2x1 handed weapons or 1x2 handed weapons making them extremely useful in PvP scenarios and as a tank. Not to mention the fact that the Death Knight can deal out some serious damage in an instant!
The Death Knight class are also well armored with the ability to equip there selves with plate armor, the strongest armor in WoW. Although they are unable to equip a shield, but there strong armor which improves the parry chance and improve there stance in battle.
Death Knights have one more unique ability to other classes and that's that they draw there powers from Runic Power as opposed to Energy or Mana.
Death Knight Guide - Advantages of the Death Knight
Some of the advantages of the Death Knight class are that they start at level 55, and are very easy to gain momentum and start leveling up fast from level 55+. The Death Knight can also continue to fight over long periods of time. They are also a great class for PvP, Tanking and Damage Dealing scenarios. Also they're equipped with a pet, they are the Ghoul and Gargoyle pet and they're pretty cool pets to have.
Death Knight Guide - Disadvantages of the Death Knight
One of the major disadvantages of the Death Knight class is that lots of people have opted for the Death Knight making it harder to get accepted in group quests as the demand isn't there.