Dennis Embo is a Catholic who was once Catholic, then joined the Worldwide Church of God, and then returned home to the Catholic faith. He wrote a book called “The God That Prevailed: One Man’s Search for Spiritual Truth from Catholic Seminary to Herbert Armstrong’s Cult, and His Amazing Return to His Faith”. See Google Books or Catholic Exchange for a brief excerpt. There is a review on the old XCG blog.
“When I left the Pasadena, California-based Worldwide Church of God (WCG) in early 2000, barely a year prior to my return to the fold of the Catholic Church, Catholicism wasn’t even an option on my “OK, what next?? list. I’d left Catholicism almost thirty years prior in order to follow the WCG’s nearly 70-year-old founder, an ad-man-turned-televangelist named Herbert Armstrong.”