Compared to everything else out there the NCR are damn near a utopia. They are democratic, actually democratic compared to pre-War USA, egalitarian with equal rights for women, ghouls and even some super mutants, appears to have rebuilt the majority of California to 19th-century standards by the time of New Vegas and from the looks of it are too big to destroy.Now, I know what y'all are gonna say: They are expansionist, stretching their resources too thin, highly tax their citizenry and throw soldiers at the enemy like they're orcs. So let met ask this: Got a better idea? The New California Republic apparently want to restore the former United States to its old glory, and the way I see it this is the only reasonable way to do so. In order to gain more resources for reconstruction you have to expand, in order to expand you need a powerful military and in order to have a powerful military you need high taxes. If the NCR citizens don't like the taxes they can just join the army or leave. If they would suddenly abandon these goals their resources would run out back home, leaving infrastructure cracked and charred for the foreseeable future, and would also allow their enemies to muster on the other side of the Colorado - which brings me to my second point:The NCR has to expand fast or else risk the Legion growing stronger. Get this: If the NCR hadn't started expanding to New Vegas, the Legion would've arrived, conquered Hoover Dam and Vegas and would be nigh-unstoppable once they reach New Cali. It was by luck that the NCR managed to halt Caesar's conquests when they got there, which eventually resulted in House reigniting his master plan.So my points are: The NCR wants what's best for the world, and the best requires making a few sacrifices - non-lethal ones, mind you. If I were living in New Vegas and had to choose between an evil, slave-running totalitarian empire, a technocratic, plutocratic dictator or an egalitarian democracy with some corruption and expansionist issues, I wouldn't hesitate a second: NCR all the way.
I say the Enclave when it still had the oil rig was the best faction rebuilding wise. Not only did they have the best tech but they were able to create new tech like power armor which is something the NCR and Brotherhood can't do. The Brotherhood is relying on what they find unlike the Enclave which created several suits of it. When it comes to the wasteland I will say what they wanted to do in Fallout 2 made sense. If they released the FEV then rebuilding the wasteland would have been easier and far less dangerous. Yes a lot of innocent people would have died, but the FEV would have gotten rid of the super mutants, ghouls(which are a waste of resources) and all of the raider groups and anything like them. Creating settlements or maintaining them would be far easier without the risk of a super mutant attack or by one of the many raider groups near the area.