I have GC2: Dread Lords, and I'm not buying Twilight of Arnor. There's no multiplayer in the game (despite many requests for the feature), and the hotseat cheat (not hack) is ridiculously cumbersome to work with. The game gets repetitive after a few games, and the AI really cheats when you set it above 'easy'.
Get the demo, and play to your hearts content, because that's pretty much it.
By the way, they won't let you install the latest GC2:DL patch using the Stardock updater. They're making you install a whole new downloading program.