I've watched several of his You Tube videos but have not read his books. He explains the use of 666 in Revelation, along with the imagery.
Elaine Pagels, another prominent scholar on Biblical history, has also written about Revelation in a book by the same name, but in the plural, Revelations. It covers and compares religious "revelations." I have not read it, but I have seen her discuss it on You Tube.
Ehrman has talked about how he went from being a Christian literalist to becoming an atheist through his studies. He uses humor often when pointing out historical facts vs. religious teachings, but in his You Tube interviews and seminars, he is not hostile to religion in general. He does speak out, though, about the political ones that use religion to attack "the other." I have only watched his free interviews and talks as a guest at various places, which are also free. He also does online seminars that he charges a moderate fee for, but donates the fees to charity.
Pagels is a historian who puts facts above beliefs and doctrines, and could be called "spiritual but not religious." She does not call herself an atheist, but also is not a doctrinaire religionist. Like Ehrman, she has a good sense of humor regarding facts vs. teachings and beliefs. Her humor is dryer and more subtle than Ehrman's, often expressed in just a facial expression when asked certain questions in interviews. She comes across as a humble, sincere, caring person with scholarly integrity.