The Good: Great new weapons, enemies, and environment, ending has a huge impact on overarching story, challenging end boss
The Bad: May be too linear for some, not many new characters, story slightly lacks
With this being the final DLC in the New Vegas saga this one is about you. You finally get to meet Courier Six, and this journey is a true test of your skills leading up to this release. This lonesome road doesn't allow you to take companions (you do find an old friend inside however), you also get new weapons, enemies, and probably the most destroyed looking area in any Fallout game so far. The game is very linear, but not like Dead Money where you just run around in circles completing stupid tasks. You go from point A to B, but it's a long road (about 5 hours actually) and there are some surprises along the way.
First off you get a detonator gun along the way that allows you to blow up nuclear warheads along the way (30 in total) to kill enemies from afar or make new paths. This is exactly what I have been waiting for since Fallout 3 and we finally get to do it. Hell you get to launch 2 different huge nukes in this DLC. The ending also makes a huge impact on the story (even if you did finish the main story). You do get new weapons which are mostly energy based, but there are some awesome melee weapons, so there is something here for every type of player.
The new enemies are Marked Men which are NCR troops that got stuck out here in the this nuclear site and turned into ghouls. These guys have many different weapons (the new Glare gun is my favorite since it acts like a semi-automatic rocket launcher). The Tunnelers are pretty tough little guys that are fast-moving, but you only run into them when you are underground. Deathclaws make an appearance and will cut you down fast if you don't have some good armor. Overall the game will provide a great challenge especially the final boss fight (required several restarts and quick saves for me).
Overall Lonesome Road provides a great challenge, new weapons, environments, but there are no real quests since you are only going in one direction. There is also only two characters in the whole DLC, so overall the DLC may feel empty to some people and too straightforward. I liked it since it really made you feel alone, and everything was up to you: Survival, the ending turn out, and saving the Mojave from mass destruction (once again). The DLC feels like the exact opposite of Old World Blues (tons of brilliant characters and quests), but not nearly as linear and hard as Dead Money.
(Based on PC version)