Frank Flynn is an Adjunct Professor of Religious Studies and has qualifications about a mile long. Not only does he teach courses covering many areas of religion, but he has also published books and articles on the subject.
In addition he was a Franciscan monk for six years so they guy knows what he is talking about when he writes about religious orders.
Here is a declaration he wrote in a recent court case where someone was challenging the religious status of the Sea Org, the religious order of the Church of Scientology. In it he compares the Sea Org with other religious orders. It's a fascinating read.
Declaration of Frank K. Flynn regarding the Sea Organization