Your poll is very very weird... Maybe this would fit in Series Discussion instead?
I like Caesar's Legion, the Van Graffs and the Powder Gangers the most.
Legion for being the most creative faction since Unity.
Van Graffs cause I like Energy Weapons and finally there's a merchant that sells them exclusively.
And Powder Gangers simply because it's a small time gang which you can actually help.
I hate the NCR though because of lots of things.
If I got to join any of them I'd probably join Legion or Van Graffs if that's not possible.