If you don't know what that is, it lets you import Fallout 3 into the updated Fallout NV engine and use it's features and mods. If you have Fallout NV and all its DLC, you might as well get Fallout 3 GOTY and use Tale of Two Wastelands. Out of all the Fallout DLC, The Pitt was my favorite. I too liked Fallout NV better as a game, but liked the setting of Fallout 3. Broken Steel just continues after the end of the main Fallout 3 quest, it doesn't change the ending.
Operation Anchorage wasn't great, but it's not long and worth at least one play through.
