Vegas is king, and the expansion with Zions National Park is awesome. I got a set of scriptures from an offshoot Mormon sect that survived and it's fun to see how Bethesda/Obsidian treated Utah area in a Fallout Universe (they did it very well, IMO).

On the flip side, if more open world is your cup of tea and you create your own role playing moments rather than relying on scripted content, Fallout 4 is an amazing sandbox, arguably the best Bethesda game experience and this is coming from a die-hard Elder Scrolls/Skyrim fanboy and I even enjoyed Starfield. Fallout 4 is just awesome, even better with the M1 Garand and 1911 mods which fit the universe well (the M1 and 1911 are in New Vegas, obviously the 1911 since a Mormon invented it. 😃 ).

While those who prefer scripted content will claim Fallout 4 has no roleplaying to speak of, by the time I finished I was the Silver Shroud superhero everyone spoke about and I had tamed the entire commonwealth, there pretty much was no random encounters anymore because I've established safety networks (through the love-it-or-hate-it settlement system) and commerce was flowing and there pretty much was no point to playing anymore. The game was "won".

I thought Fallout 3 was too short, but it was fun. I really only recall the Aircraft carrier and endlessly walking through subway tunnels. Then I had a small battle and all of a sudden the end-game screen showed up. "We are done now?" But the Brotherhood of Steel was a fun faction in Fallout 3. 3 started the modern" fallout craze and is still a very fun game, but New Vegas is more refined.

I have not played Fallout 2.

Fallout 1 is a blast if you like retro gaming. I can only make it about 1/3 of the way through, I need to try it again. It's a brutal old-school RPG from an era where gaming doesn't hold your hand and especially the early game can be a grind fest. The humor and story are great and winning it is going to feel like an accomplishment (if you do manage to complete it). But it's an old-school isometric RPG, not first person, so game play is going to be more cerebral and less twitchy, but it's still fun.

It's a good franchise.