Smert sum it up well, those who expect a "traditional" Fallout RPG and Stories wouldn't be disappointed. But those who expected FO3 sandboxness would. Personally I cannot believe I put a thousand hour in FO3 after I played New Vegas a couple of hours.
If i had 2 say i was ever so slightly disappointed love how people make out the story is a masterpiece thats my biggest beef with nv.
It's about all the freedom of choice, and that your decision does make quite an impact at the in game and end game battle (especially Yesman route). The story have enough twist and buildup to keep player pushing forward (with a lot of FO3 sandbox fan pass the point of no return).
saying its about quality is abitrary, every aspect of the game is not quality, how they did the story was pretty good but the game world has a huge lack of things to explore, no random encounters at all, none of the factions patrol anywhere, the spawns are all static, and the most of the map is just empty, just cause its a desert isn't a reason to leave it empty. so certain aspects of the game were quality, the dialogue, the weapons selection, the reputation system, the skill/perk system, but to say its all quality, not having any random events or encounters is a lack of quality, and having so much of the map barren isn't quality either.
Actually, the map is pretty cram compare to say FO2, which have a lot of empty land you only see as the world map.
Random Encounters isn't a strong argument either, as they are poorly done in FO3 at best (so random that a lot of people encounter the Alien Blaster 1st and one shot by Raiders), wastelander in the middle of no where talking about taking refugee at Underworld or other town also seems odd because DC is more dangerous than the rest of Virginia and Maryland. It is also odd that wastelander fighting creatures not in their territory.