New Vegas is pretty amazing. I'd call it a must play for fans of WRPGs, honestly.
Fallout 3 and 4 might as well be the same game in my mind. 4 is more casualized, but both suffer from pretty bad Bethesda writing. Which is what I want from RPGs.
So, coming from someone who doesn't like Bethesda style open-world games--I can't recommend New Vegas enough. It's just that good.