Well this is a two parter really I'm one or two quests from getting into New Vegas and I am kinda liked by NCR and the legion leans to liking me. I came across a battle in which legion and NCR were in a battle but i couldnt decide who to back to i just watched and took the loot of the dead (NCR won).
So what is more fun/intersting/worth it to side with? NCR or The Legion.
Part 2 is who is more fun/interesting/worth it to side with overall in the game mr house, ncr,legion, i think you dont pick any side and make freedom across the land (idk maybe)

Your heart.

Choosing a side is part of the fun of the game. They're all interesting. Pay attention to the dialogue and respond accordingly.

I find it most fun to really role-play; to make a character with a personal code and agenda, and then work along with the faction that best suits that code. I actually have three characters: an ex-raider who likes the Legion, a drifting gunslinger with a technological bent who likes Mr. House, and a bleeding heart pacifist who will probably end up backing the NCR.

But if you don't have a particular character direction in mind, just be yourself and join up with whoever you like the most. Don't even plan ahead. Take things quest by quest and see what happens.

Be true to your character.