I'm not a WOW player, but this is an amazing game. Fun to play, easy to teach and enough variety to keep me coming back for more.
A normal game runs about 2hrs, but if everyone knows how to play it's a bit faster. Over a game you will level up your hero by defeating various nefarious creatures and collecting the loot they drop. The objective of the game is to be the first to 8 victory points. You earn these by completing various quests, such as kill 3 undead monsters, fly to Ironforge City and be the first to get to level 2 etc.
Overall it's a great game and scales well with 2players, or 6players (with expansion characters).