Don't worry about the brand, just go to the peanut butter section and check the ingredients section as mentioned. Natural peanut butter will say: "Peanuts" or "Peanuts, salt".
The stuff doesn't taste any different to me, I think a lot of the crap they put in jiffy and whatnot is mostly to give it that great consistency it has. Natural peanut butter is like slime when its first opened and when almost empty it starts to get dry and harder. It still tastes great though.
PB has a lot of calories, but the fat in it is considered "good" fat from what I've read.