Dead Money: A tedious slog to get some good rewards. I have to wonder if Obsidian was trying to make the worst looking Fallout DLC, because they nailed making the Villa a total eye sore (loved that one area that had a shit brown tint, they really outdid themselves there). God is the most irritating companion in any of the Fallout titles, he never shuts the fuck up about wanting to wear my Pip-Boy around his neck. I will contend that Father Elijah was a genuinely good antagonist, and the backstory for the Sierra Madre was fascinating.
Honest Hearts: The least baggage amongst the New Vegas DLCs. It could've had more content, and it was a missed opportunity to not allow Legion players to side with the White Legs, but I never had any tedious moments while playing it. Probably has the best weapons out of them all, I adore the Survivalist's Rifle and .45 weapons.
Old World Blues: Other than the 30+ minute dialogue intro and bullet sponge enemies, this is the best New Vegas DLC, maybe even the best Fallout DLC period. The map alone is such a joy to explore even after several playthroughs, and I loved the bonus Perks you can acquire throughout the DLC.
Lonesome Road: A different sort of tedious slog with decent weapons. Ulysses is a fucking waste of all that buildup.
Overall, I find the DLCs to be the most inconsistent of the series. The best highs, and the worst lows.