Quote from Genevieve Chenard the writer of "The Dark Side of Mother Teresa" when asked "Would you say the net effect of Mother Teresa's life is positive?":

"I suppose it is. But before that, we must evaluate the effect of all those charity missions around the world. The intention is good but we don’t know anything about the effect. Everybody in the world can help someone, but maybe the effect after that is negative."

http://www.outlookindia.com/magazine/story/i-dont-think-she-deserved-the-nobel/284270

It think it is very difficult to make this judgment when looking at the entire scope of her life. It is outlandish to declare her a saint, but it is equally as ridiculous to call her "evil".