The same as my opinion of all cults: An abusive indoctrination system that has wasted innumerable human lives with its insular delusions and anti-individualism. There were thousands of obscure desert cults in the ancient world, and the fact that this one happened to survive is the only reason why today we treat it any differently from Zeus or the moon goddess Nanna. It is a self-sustaining brainwashing organization that survives by emotionally abusing young people, making them feel as though they only have value as part of a greater community, and transforming them into unthinking, unquestioning followers of doctrine and scripture. The moment that we as a species banish it from our moral philosophy, our lives will be incomparably improved.
I see the word cult and you lost me. You know what cults are? Cluts are based on people, they associate with each other and shut off everyone else, they are unified under one real leadership, they don't let people leave, they blackmail people, they controll every aspact of the members lives.
You're talking about an international, leaderless, personal, dissolved, open religion. In fact there are thousands of types. A cult has one leader, and no single person is a leader of all Christendom. (That's a good thing, by the way.) While a few of those types do fit the description, most of them don't.
Cults and religions are different. Too many people think they are the same.