Imma give it a rough estimate and say 75% of my runs have been independent, 12% have been NCR, 12% have been Mr House and 1% have been Legion. I did Legion once and am currently in the middle of a Legion run. But it's super rare for me. So between the two, NCR.

Mr. House and NCR. Currently doing my second playthrough and siding with Yes Man

True to Caesar

Usually NCR, sometimes Independent.

Of these two, definitely NCR.

Yes, it has its blatant corruption and uncaring politicians, but compared to the legion? They're saints.

Crucifying whole towns and setting them ablaze, committing genocides, slavery, sexism, backstabbing your allies, pretty much outright fascism as described by its very founder, that's a big negative.

The only good thing the Legion has going for it is that their roads are safe... But that's not worth the sacrifice by a very long shot.

All though Caesar’s legion is horrific but their roads are safer and NCR soldiers are annoying like they couldn’t even clear Primm. Also I hate their voice lines like “are you lost 🤓” “patrolling Mojave makes you want a nuclear winter🤓🤓” Also they just boring overall like legit super NPCs. Caesar’s legion has a great design and lore like returning to Roman era seems interesting in a post nuclear apocalypse

^or "when I got this assignment I thought there would be more gambling"

Independent 99% of the time. You have a choice between Disney (House), cheap and much worse Rome, and Politicians (NCR). None of them sound like a decent option. I would side with Raiders before these people.

The only con of siding with legion is death of house, Andy, and Boone

I quite wonder who would join the Legion after seeing what they have commited for no compelling reason in Nipton. I mean, to join out of conviction, not just to try it as an RPG player. And Nipton is very probably the first place for everyone they are encountered at.

I heard people complaining that NCR are commies, collecting taxes for nothing. I think they are the only ones far and wide who strive to build a real state and civilization, they centralize because all states and offices are a product of centralization (unaccustomed in a wasteland). All states are corrupt, more or less.