Much like the first two New Vegas DLCs, this one isn't nearly as good as it could have been.
You enter the Divide and see an area that looks like it was hastily thrown together, but still manages to show the basic idea of the Divide. The setting's unique for New Vegas, but feels like the ruins of Washington DC from Fallout 3 have been thrown into a canyon. The fact that the Gamebryo engine is well out of date doesn't help the image, the world often looks blocky and the storms look like cheap, dusty waterflow textures in the sky. However, some interesting features are added, such as a semi-destructable landscape, something that's not been done on this engine before.
You're given the ability to explore this landscape with ED-E, who will occasionally send you logs that tell you his story. Unfortunately, ED-E's story is more interesting than the main story of Lonesome Road. Throughout the landscape, you'll fine many new and useful weapons, such as the Red Glare rocket launcher. LR has more good loot than Dead Money or Honest Hearts, but less than Old World Blues.
The story and questline isn't that interesting. You have to fight your way through hordes of new enemies, as well as deathclaws, to get to Ulysses. Ulysses is just a mad man who wants to nuke the NCR because he thinks they have a warped view of the future. His character comes across as boring, though, due to the awful voice acting.
All in all, although Lonesome Road adds some new things to New Vegas, they often turn out to be over-hyped. Much of the game is repetitive fighting along one road, the RPG element has been completely removed from this DLC. Although it's more interesting than the first two DLCs for New Vegas, it doesn't live up to the excellence that Old World Blues was.