As with all cults, educated and thinking people leave it. With the Ahmadiyya, it is especially difficult to leave as there is complete social isolation within the cult, with no external social and/or family ties allowed. Therefore, the vast majority of those who leave do so slowly and silently. Here is a list of some prominent people who left openly.
Hafiz Bashir Ahmad Masri, scholar
Father of Arif Abdul Mateen, Urdu Poet
Hamid Ahmed, Entrepreneur, Karachi Pakistan
Z A Sulehri, editor of Pakistan Times
Munir D. Ahmed's grandfather and himself
Maulana Lal Hussein Akhtar, scholar
Hassan bin Mahmood al-Odeh (Director of Arabic Programming/Publication of Ahmadiyya), Ahmad bin Mahmood al-Odeh, former President of Ahmadiyya in Sweden, and their brother, Salih bin Mahmood Odeh. They are from the Kababir clan, the only Arab presence of the Ahmadiyya. Hassan wrote a detailed book about his experiences.
Ahmad Karim Shaikh, co-ordinator of clandestine missions of the Ahmadiyya and founder of the http://ahmedi.org web site
Shahid Kamal Ahmad, founder of https://thecult.info web site. His book is embedded at the bottom of this page.
Ibrahim Lamholt, from Denmark
Tamim Maaita, Jordanian
Ahmad Hussain Abu Sardana, of Gaza
Saleem Al-Jabi, of Syria
Ismail Babatunde Jose of Nigeria
Ibrahim Abu Nab - journalist - published four articles in a Kuwait daily about Hassan Odeh's departure
Alhaj Abu Bakr Saeed and S.P. Tayo of Ghana (circa 1974)
Dr. Ismail Balogun of Nigeria, author of "Islam versus Ahmadiyyah in Nigeria", published by Sh. Muhammad Ashraf, Kashmiri Bazar, Lahore
Shaikh Amri Abedi, first black mayor of Dar es Salaam and close advisor to Julius Nyerere, and Minister of Justice of Tanganyika (disputed that he left, TBD)
Ahtesham-ul-Haq Abdul Bari of Bombay, India
Shaikh Raheel Ahmad, a scholar from Germany
Muzaffar Ahmad, a poet from Germany
Professor Munawwer Ahmad Malik, Pakistan
Miklos Molnar, former General Secretary of the Ahmadiyya in Hungary
Usman Barry, Ireland
Akber Ahmed Choudhry, author of this site, and children
Amjad Saqlawy (Jordan)
Osama Sayed (UK) and family
Khalid Jamal Ahmad (UK)
Fouzia Faizi (US)
Raeesa Toor (pen name, UK)
Omar Wasdan (Morocco)