That's interesting, because their origins are quite different. As best I understand, Opus Dei was started in Spain by Josemaria Escriva, and TFP originated in Brazil. Opus Dei seems to be a little savvier than TFP - just compare their websites: http://www.opusdei.org vs http://www.tfp.org. Opus Dei creates an impression of being more generally palatable. If you get into TFP's site,
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Abusive and Controlling Relationships