I love this game. I bought it twice and I have no regrets. I love almost everything about it.
Let's start with the visuals. It looks similar, if not, near identical to Fallout 3 which isn't a bad thing. Fallout 3 looked pretty good for a 2008 game with some ocasional low res texture here and there.
Sound design, is what you expect from a Fallout game at this point with the good ol' radio stations with plenty of songs from the 30's, 40's, 50's, among others, that still hold up even today. Weapon sounds are slightly changed to feel more like guns instead of slightly sounding like toys, from Fallout 3.
Story, is nothing too great, but it's compelling enough to make you think about it. Who's in the right? Who's in the wrong? Did you make the right decision? While were at it, yes, you have important choices, not only with side-quests but also the main storyline that affects the ending outcome and it's all shown to you at the end for you to see it's fate.
Gameplay, it's identical do Fallout 3 only this time you got actual iron sights aim (You can also change it back to F3 in the options if you so desire). You still have VATS for that Turn-based feel. You get more weapons to choose from and most of them feel great.
Characters, are very memorable. They all have personalities, several of them even have great backstories. I really like the characters.
Exploration, unfortunately, is the weakest part of the game. In Fallout 3, it was fun to explore and wander off to wherever you pleased, because you were sure to find some great loot and tough enemies to fight. There's none of that here. It was disapointing then, it was disapointing now. New Vegas, the place named after the game, also isn't anything to write home about. It's feels unfinished.
With all that said, I really enjoyed this game and played dozens of times with different builds and branching choices.