Isshiresshi said:
Fallout 3 is a lot more "humanity is suffering from nuclear war and everything has gone to hell"-atmosphere and the story too is more focused on it as well, where New Vegas has a "did not get hit near as hard with nukes like everywhere else"-background. The story makes a lot more sense from the start to finish then New Vegas does.
They both play like each other. No different in the graphic or mechanics from the two games.
Fallout 3 has some interesting things as well as New Vegas so I think you should try and make it work so you can try it out!
Past the first sentence, every single part of this post is false.
Fallout 3's story makes absolutely no sense at all. It takes place 200 years after the Great War, but is designed as if it were 20 or so years ago. Pre-war computers still function and pre-war food is still edible. Enemies that were wiped out in FO2 suddenly have legions and legions of soldiers to throw at you from helicopters. Super Mutants are somehow all the way over on the east coast even though the FEV plants only existed in the southwest. There are vampires and organizations dedicated to robot emancipation. People continue to survive even though you'll never see anyone making any effort to--no one scavenges or tries to grow crops or anything.
The Raiders outnumber the settlers, so one wonders who they're raiding. There's a group of children who have survived as a child-only colony since the War, even though they kick all the people who reach breeding age out. And finally, the main point of the story (water purification) is completely undone by high-school science. Suffice it to say that there is no way the water would still be irradiated after all those years.
The mechanics are also quite different; New Vegas features iron sights, takes away that garbage where you take way less damage while in VATS, makes numerous small tweaks to the gunplay and reworked the perks system while changing some skills around and adding hardcore mode.
Don't listen to this guy. What you are missing by not playing Fallout 3 is the utter ruination of the series, but admittedly, it does have some pockets of really cool atmosphere. That's usually undone by the sheer idiocy of the plot and dialogue, however.