Non Denominational is best, because Christians who are denominational, basically believe what they're taught, because of their church's doctrine, whereas nons will usually tell you what they believe, and give an explaination as to why they believe it.
I'll tell you why I believe something. I won't merely say it's because of my church's doctrine.
I'll tell you why I believe something. I won't merely say it's because of my church's doctrine.