Andrews deserved the Oscar, absolutely, for her scintillating performance. Ironically, both Bancroft and Stanley were American actresses playing Brits but both of them had some problems with the accent. I strongly prefer Bancroft over Stanley, though, because I think she got more right in her role than Stanley did in hers (she was upstaged by Richard Attenborough and her own discernible Method acting). Perhaps Geraldine Page would have been better than Stanley.
"I'm not afraid, Mother. I'm not afraid."
Kind of unrelated to the thread topic, but it's interesting that you mention Geraldine Page. While watching this film I kept thinking to myself that Stanley bears an uncanny resemblance to Page.
I've always thought that Kim Stanley and Geraldine Page seemed alike, with each being as totally annoying as the other.