As someone else who prefers 3, I think that it’s more fun to explore and generally has a better atmosphere. New Vegas has better writing but the world feels empty. 3 more fun to actually play. Honestly, I’d probably take 4 over NV for the same reason.

1/2 I haven’t managed to get into. At all.

ETA - I was also never really interested in the wild west as a setting, so NV has a bit of an uphill battle from the start.