I just spent a long time back in F3, playing various characters. I like the overall gameplay of F3 because it allows a greater degree of good vs. evil: it seems like in NV, you are forced to do bad things no matter who you side with. More realistic, maybe, but more confining. And no matter who wins, people who don't deserve to suffer do. Still, I will say that NV allows the player a greater variety of quests and outcomes.