In Fallout: New Vegas, the player has the option to assist many different factions over the course of the game. Via both main quests and side quests, players must make a definitive choice by the end of the game regarding which faction they support. This choice can lock them out of helping other factions after that point in the story. This is something that the player will have to consider as they progress through the game.
The New California Republic or NCR, is one faction that, when joined, locks the player out of supporting Mr. House and Caesar's Legion. Despite this, the NCR can be a very enticing faction for the player depending on how they choose to role-play. Whether it's their democratic sensibilities compared to other factions, or simply that they're the most militarily capable, players have several reasons to consider joining the NCR in Fallout: New Vegas.
6 The Only Working Democracy
While the NCR is flawed (what civilization isn't?), it is without a doubt the only post-war nation in Fallout's America to feature a democratically elected government. Compare this to Caesar's Legion, which is held in an iron grip by Caesar himself at every level.
Mr. House also describes himself as an autocrat, albeit one who is less prone to human mistakes by virtue of being more machine (which may not be a good thing). Players who value freedom and the idea of checks and balances on authority (relative to the other post-war nations, that is) ought to consider siding with the NCR.
5 Respect For Human Rights
When the bombs fell in 2077 and, in Caesar's words, "reset Humanity's cultural progress to zero," one of the things that was lost was the notion of human rights. The wasteland has seen its fair share of barbarism in the decades since the Great War, whether from Caesar's Legion and their affinity for wanton crucifixion, or an army of crusading super mutants hell-bent on eradicating the human race. Indeed, muman life has lost most of its value in the post-war world.
The NCR, however, is unique in that it is more respectful of human rights than virtually any other faction besides the Followers of the Apocalypse. People in NCR territory enjoy freedom of speech and religion, as well as protections against various forms of discrimination. There is also a court system protecting citizens and non-citizens alike. These protections are slowly integrated into the territories that the NCR annexes, which would mean the Mojave at some point should the Courier support them in their conquest of the region.
4 NCR Loot Is Second To None
Like many factions in New Vegas, having a high enough reputation with one will result in that faction rewarding the player with various bonus that they may or may not be interested in.
In the case of the NCR, they will be gifted a safehouse with lots of good weapons and equipment such as Ranger Combat Armor and Salvaged Power Armor. They'll also get a radio that can be used once every 24 hours to call in for either troop support or supplies. Ranger Gomez will also visit the safehouse every so often, giving the player the opportunity to request a refill on certain ammo types.
3 Caesar's Legion Isn't Built To Last
Upon Talking to Caesar and learning more about the Legion, it becomes obvious that it likely won't survive for long after he's gone. For one thing, Caesar has a very backwards understanding of history and rather poor foresight. He doesn't consider for one second the idea of someone other than himself being in power (namely, Legate Lanius), or what will happen after the Legion has no one left to fight.
He relies on the idea of his conquest of the NCR transforming the Legion into the perfect society for arbitrary reasons. Compare this to the NCR, which managed to survive decades after its founders died due to its unifying force as a national identity, rather than a single man.
2 Greater Possibility of Long-Term Alliances
The NCR demonstrates a capacity to work with local tribes and even opposing factions when the time calls for it. Nowhere is this better demonstrated then how the player can make allies out of both the Great Khans and the Brotherhood of Steel, two factions that the NCR has gone to war with.
Both Caesar and Mr. House are more self-serving when it comes to alliances. The former has a reputation for betraying every ally it ever had, and the latter isn't willing to compromise with factions he looks down upon. While the NCR is rough in its own way, the ending slides of New Vegas portray it as the most flexible faction when it comes to getting along with others.
1 Distrust of Mr. House
It's entirely possible for the player to come away from their meeting with Mr. House with a sense of distrust of motives and intentions. House is essentially a techo-autocrat who believes that technology can solve all the world's problems, especially if he is the one behind said technology. As such, he has become increasingly removed from his own humanity.
For all its faults, the NCR is quite the opposite. It only functions on the trust of its people, making it fundamentally a more human organization. For players with a more humanist outlook, House is essentially a no-go.
Fallout: New Vegas is available now for PC, PS3, and Xbox 360.