Fallout is boring. Dull and dead atmosphere, only few styles to play as (sniper outdoors, rifle in mid-close combat, heavy weapons when facing bulky enemies). Also fallout 3 was pale compared to the other fallout games that had more rpg elements. Fallout new vegas is better in the sense that there was no good vs evil like brotherhood of steel vs enclave.
Although, bethesda might have learned from their mistakes, like the forsworn conspiracy and the civil war. No real good vs evil.
But skyrim has more play styles, a world that is alive, and better quests.