I'm a well seasoned ( ;)) PAM user. I previously used Crisco, but just found it difficult to get in all the little nooks and crannies. Especially when doing gem pans and waffle irons. So I love the spray stuff. I do 2-3 coats at 500 degrees, 30 minutes each. Folks I sell too always ask how I season because it's so non-stick.
Can't say I'm too worried about additives. You can get cancer by spending too much time outdoors in the sun, so I'm not going to worry about some additive in PAM.