We are both lungs of the "true Church" united in valid Sacraments as our Orthodox brothers here on FR often said.
Dear SFA, there are many a Catoic and an Orthodox Christian who will disagree. For one, I have been told very recently by one FR Catholic that while the Orthodox sacraments are "valid" they are not eficacious.
He quoted a 15th century papal bull that states that no schismatic or heretic can be considered part of the "true" Church (which means in communion with Rome), and reminded me that doctrine is not subject to change.
For their part, many an Orthodox will tell you that as long as we don't profess the same faith only one Church is "true."
This is one of the reasons why I decided to leave the Church and consider all things religious as man-made agenda.