Fallout provides the player with a unique customization and puts the player right in the game. The world provides a rich post apocalyptic land and is filled with danger and surprises. Great game for both hardcore and casual players.
they are both extremely great games in story line and game play. and i do agree that there are some things better in Fallout 3 but in the long run Vegas is better. on a personal bases i like the story better, the graphics and the game mechanics.
The story for Fallout 3 is a bit more immersive. You gain attachments with "dad" since the start and actually feel like you want to rescue him. New Vegas on the other hand is pretty much "Vengence". Also, the thing about the Main Character just being a courier didn't make him seem really special.
although this may be true vengeance in its own aspect is pretty immersive in its own special way. being a courier i admit could have been a little less lame. but in Vegas the fact that you can have special perks like swamp lands that make glitches happen on purpose is pretty awesome.