General Brazilian
comportar-se com cuidado; agir com cautela
common usage in formal and informal contexts
São Paulo
se comportar com cuidado
standard usage, common in business and diplomatic contexts
Rio de Janeiro
agir com cautela; se portar com cuidado
informal usage prevalent in conversational Portuguese
Portugal
comportar-se prudentemente; portar-se com cuidado
formal usage, common in literary and official contexts