I'm with this guy, but yah I think fallout NV wasn't as successful as Fallout 3 because the bad cred it got from bugs at the start, but Fo3 always had the better replay ability in my opinion, sure NV had 4 endings but there all kinda doing the same thing.
Fallout 3 story > New Vegas story
Fallout 3 plot > New Vegas plot
Fallout 3 characters > New Vegas characters (very close)
Fallout 3 gameplay < New Vegas gameplay
Fallout 3 character development < New Vegas character development
Fallout 3 sandbox > New Vegas sandbox
Fallout 3 setting > New Vegas setting
Fallout 3 replay value < New Vegas replay value
Fallout 3 graphics < New Vegas graphics
Fallout 3 weapons < New Vegas weapons
Fallout 3 armor/headgear < New Vegas armor/headgear
Fallout 3 perks < New Vegas perks