Check the tropical traditions link. In short, the lesser the quality, the more it's processed and it's mostly just for removing the scent. If you're doing hair and body you may want to get a refined version if you don't want the smell. However i absolutely LOVE the smell of coconuts, so i get unrefined and use it all the time, i'm a guy and it makes my hair look REALLY nice when i slick it back. Gives it that kind of greasy slick look, but it's not greasy at all, it's amazing.

It doesn't have a huge difference. However... I am warning you, that it takes a few washes to get the coconut oil out of your hair! ;)

The process is unlike Olive Oil production. This site which I have no affiliation to has good info http://www.tropicaltraditions.com/what_is_virgin_coconut_oil.htm .