Honest Hearts is the second DLC for New Vegas, and the first I played.
The main plot focuses on the conflict between several tribes that have taken up residence in Zion National Park; the savage White Legs, the peaceful Sorrows, and the helpful Dead Horses. This conflict however, is ancillary to the characters that you meet during it. Joshua Graham is the highlight; the soft-spoken ex-Legate helps keep your main quest in mind throughout the entire adventure, while being an interesting character in his own right. Your other companions also have very defined personalities and engaging back-stories despite the short time you spend with them, and Daniel's conflicted leadership of the Sorrows made me sympathize with him a lot.
The plot isn't anything to write home about, but the characters drive it, and they do it wonderfully, with the same level of writing and voice acting present in the main game. The only thing I'd complain about is the White Legs; an Always Chaotic Evil
faction doesn't sit right in a world with Grey And Gray Morality
, and the inability to side with them doesn't make sense since you can side with the Legion otherwise. I don't play evil paths, however, so this hardly bothered me.
Gameplay-wise, it's more of the same, perhaps slightly harder since you can't bring much equipment with you, and because of the slightly higher enemy density. It adds a bunch of crafting recipes that make the system more valuable, which ties into the whole wilderness survival feel quite well. And one of the parts of the main game that I loved was exploring and scavenging, and this add-on doesn't disappoint in that regard.
SUMMARY: this is a great addition to the game, adding more great writing to experience while lacking the difficulty barrier of the first add-on. If you enjoy Fallout because of the characters, or the feeling of exploration while digging through abandoned buildings, this is worth the ten bucks.