Awesome Game. One of the Top 10 games ever made. Disclaimer: I played Fallout 4 before this game, and Fallout 3 was my first Fallout game.
The interaction between factions in this is excellent, so is the interaction between companions and factions, which really is the one way this game outshines Fallout 4. The story in this is great too. I just wish that you could play after you beat the main story like you can in Fallout 4, but Obsidian had a tight schedule for getting this game out, so there wasn't any time for that. That's the most fun aspect of RPGs in my opinion as then you can see the ramifications of your choices firsthand instead of being told them in a post-game narrative. This makes you have to play the DLCs before beating the base game, which in my opinion is backwards, which is a way Fallout 4 outshines this game.
The best reason Fallout New Vegas is better than Fallout 4 IMO is there are not any procedurally generated repeat quests (aka: "Another Settlement needs your help", or "I know the location of another pre-war artifact"), which was the worst part of Fallout 4 because it's time consuming and boring.
The way the Brotherhood of Steel is treated in this game also makes me a little sad. Siding with the Brotherhood of Steel in Fallout 4 is a major plot aspect, but in Fallout New Vegas, they are a weak and defeated faction. This isn't a bad thing as it's part of the story, but it just makes me sad.
Overall, this is a great game. Fallout New Vegas does some things better than Fallout 4, but Fallout 4 does many things better than Fallout New Vegas, so i really can't say which is best, nor does that matter because they are both incredible games.
