Since this has degenerated into "why the legion svcks" vs "why the legion is awesome," let me just point out one thing.
The legion are liars. Aside from being rapists and slavers and cannibals, they will bold-faced lie to you, in order to make their heinous traits seem noble.
The Legion have been proven to be quite honest about their endeavours. Unlike some others at least.
Remember Nipton? Remember how you were told that no one even fought back? Did you actually look around? Because if you did, you probably noticed something in the Trailer park area. A dead civilian, with a laser rifle. And next to him, a pile of ash with legion armor. Almost like they DID fight back.
The Legion picked Nipton, not because it was evil and needed to be purged. They picked Nipton because it was EASY. Most of the town was high, and couldn't fight back. The rest could be bought off and double crossed.
That would imply the Legion purges every town they come across, which is a lie. Take Primm for example. Nipton served no purpose to the Legion and was ultimately better off not existing.
Remember Cottonwood, and how the Legion calls the NCR weak? They tell tales about how the scared NCR won't attack them, and how brave Legion troops go out and attack all the time. Do you also remember the Brotherhood scout between Forlorn Hope and Nelson? A neutral 3rd party tells a much different story. Both groups are scared. Neither are willing to actually attack. So much for the bold and daring Legion.
Been a while since I've played the game so I can't really comment on this.
Also, anyone with a wife, sister, daughter or mother, bear in mind that she will be sold off into prostitution under the legion rule.
Prostitution in a sense I guess.