If you have Fallout 3 modded then no, it isn't.
FNV is better in almost everyway. The story made a lot more sense, the story had choices to make, it had actual radiant quests, faction reputation, weapon modifications, there were more weapons, ammo types(Incen,Explosive,HP,AP). Then the mods, Warzones, Project Nevada, MISERY, Weapon Catalogues, that's all you really need for hours and hours of fun.