Not for everyone
2007's Lord of the Rings Online: Shadows of Angmar was a noteworthy challenger to the established juggernaut of Blizzard's WoW, and as great as it was, it suffered from a bit of me-too syndrome. Most of the game mechanics were borrowed and slightly tweaked versions of its bigger, flashier cousin, but LOTRO succeeded in many ways that WoW could not, carving itself a niche market of lore-nerds and mature players. Fast forward to 2008 and Turbine has done something amazing -- they released an expansion that looks, feels and plays nothing like the King of the Playground.
The Mines of Moria expansion changes some mechanics of the game and adds an interesting new weapons system, but you'd be remiss to think that there's anything close to resembling Moria itself in the current MMO market. Where as a max-level character in WoW can walk the world with relative impunity, tossing aside mobs with reckless abandon and avoiding such pesky trivialities like paying attention to your health, Moria is dangerous at every turn, no matter how tough you think you are. Creatures can knock you off ledges and kill you with fall damage, labrythinth-like passages through make-shift orc camps can land you face to face with a pack of mobs that will make short work of you, and getting lost is almost always a problem, with few areas that allow a direct line between point A and point B.
Despite being mostly underground (the expansion includes two outdoors areas, to the east and west of the mines themselves), Moria feels incredibly expansive and amazingly varied. From the steam-punk inspired waterworks to the stuffy and sweat-inducing lower levels, Moria never fails to amaze. Toss in new dungeons, new raids and expanded session play and you have a winner, but with a caveat: Moria represents a slower and more methodical, more stressful questing environment. The dwarves really did dig too deep, and their grand city under the mountain looks more like a giant tomb for player characters than anything else.
Adventurer be warned.