Spending time in Fallout is great! I've yet to finish 4 because i'm exploring everything before i do the main quest. (used a mod to start the player outside the main story, so im free to explore without having to deal with the urgency of the main quest - because the world in F4 and it's quest aren't compatible, imo), but it's still great to spend time in the Fallout worlds! Haven't played 3, but someday i might!