The tribes in the area before House showed himself were nomadic, moving around the Mojave area. House scouted them out. He sent out his securitrons to meet the Boot Riders. At first they destroyed the ones he sent. But then he sent a lot of them. So the Boot Riders became the Chairmen.
There wasn't much going on in the Vegas area before the NCR showed up. Mr. House set his plans into action. Made deals with the NCR. Then the Legion showed up and the rest his history.
Not sure what Culture there is, depends on where in Vegas you are. On the Strip it's an attempt to remake the pre-war culture, guided by House. The areas around the Walls of the Strip are new cultures.
Pros of the city of New Vegas. Water, food, power, entertainment and a safe place to live. As well as industry, well future industry. Basically House's dream of bring technology back.
Cons would be all the negative trappings that come with civilization. Greed, Corruption, Drugs, Wealth barriers and so on.
Ulysses does have this to say about New Vegas: "Families of Vegas were once tribes. Got drunk on the Vegas lights, the spirit bled out of them. Old World history, under a different flag. Whatever traditions or rituals they had, most likely squeezed out of them by now, turned into something else. And if not, then I'm afraid what's going to happen when they come creeping back. Everything in Vegas speaks of someone who can't let go. House takes a shovel to history's graves, props up the dead, then puts words in their mouths. The tribes don't even know how they were broken. Not a world I want to be part of, going through motions until we're all smiling faces on some robot's screen."