I appreciate /u/searocksandtrees citing me. That gets a lot of the work out of the way so I can just speak frankly:
From everything I've seen surrounding her character it seems she is just the charitable person people claim of her and did so in the worst of conditions. However the scale of her work is heavily embellished and her notoriety surpasses the actual scale of her work. To make matters worse, she seemed to went to an extreme with her vow of poverty so it affected the quality of the work and living conditions (there is the oft mentioned story of her being given a free building for her people to work in NYC and her turning it down as the elevator that city hall required was too luxurious for her) but seeing as these standards and medical availability are an issue to the area she was working anyway it is questionable what was her doing and what was consequence of the area she was in. I'd redirect you to my post cited by /u/searocksandtrees for that detail.
Overall, Hitchens' picturing of her as a monster doesn't hold to criticism but there is still much wrong to be said. Especially in what could have been done if she didn't apply her vow of poverty in that way. Contrast that to the current Pope Francis who also is under a vow of poverty but lives in the Vatican in the Apostolic Palace
Hi, not discouraging other responses here, but you may be interested in some earlier threads
several flaired users in AskHistorians consensus on Mother Theresa.
/u/Dice08 answers here The top of r/All says that Mother Teresa never helped anyone. Is that true?