The only bugs I'm worried about are the Cazadors
The game world is obviously similar in feel to Fallout 3 and with the exception of the companion wheel, plays much the same in terms of navigation, dialogue, and combat. However, the developers took an entirely different approach to the story. Where Fallout 3 was a story with many twists and turns leading to essentially the same outcome, New Vegas leaves the ending up to you. Along the way, I am constantly struck with how interwoven the quests are and how deep the story goes. Many have commented that the storyline isn't as compelling as Fallout 3. I would argue that the story is just as compelling, but much more involved and therefore harder to get your mind around.
All in all, I am sitting at the console with the same "I don't want this to end" feeling that I had with Fallout 3. I tell my wife, who doesn't understand why a grown man plays games, that RPG's like Fallout are really no different than reading a really good book except you are helping to write it as you go.
By the way, after 150 hours, I have still not completed the game--not even close. I could finish it in a few hours (thanks to the wiki's), but I want to walk every inch of the Mojave first, meet every person, and complete every quest I can. If you haven't already, play Fallout 3 first. Then, move out west and live, love, and kill in New Vegas.