New Vegas polished some of the things from Fallout 3. However, I liked Fallout 3 better. Maybe because I played it before New Vegas, I don't know. For example: Aim down SIghts in F3 is just a slight camera zoom. In NV you actually Aim down the sights of the weapon. Factions: In F3 it was hard to know where you stood with various factions and karma came into play with a lot of that too. In NV, you have a tab on your Pip-boy that tells you where you stand with various factions. You can also wear disguises to sneak past people from a certain faction if they're hostile towards you. New Vegas' story seems to allow you more freedom and choices matter more. Fallout 3's story is somewhat linear but personally, I liked it better.