Read This first before continuing.
Without a doubt I can now say Hunter X Hunter 2011 has less filler per arc (You could say less content per arc) and is censored in comparison to its 1999 predecessor. Here see for your self.
One other thing I would like to point out is the 2011 version has overly bright colors. It clashes with the mood of the anime. A bright, colorful pallet kills the suspense the story’s trying to build. (Pun intended) While I could care less about the amount of violence I do care about the atmosphere of the story. Even though the stories are the same Hunter X Hunter 1999 is darker because of the way it is presented. I’m not talking about blood and gore here. That’s how a child would think. Even without those things the 1999 version is more mature.
The only reason I bring this up is because the vast majority of people are drawn towards violence in media. While I recommend watching Hunter X Hunter 1999 for the filler which is extra content the vast majority of people reading this will watch the 1999 version because of the pictures shown above. More blood does not equate to more mature. In this pituitary case it may seem that way though.