While there are some flaws in this movie, it has held up well over the years.
The plot inter-weaves a love story with a morality allegory -- no easy task. This movie does a credible job at both.
Miriam Linka, played by Elisabeth Mueller, is convincing and charming as she evolves from a frightened but strong concentration camp refugee torn between anger, hate, and disillusionment with an inner desire to love and be loved, while at the same time striving to maintain an inner idealism.
I suspect there were significant cuts in the story line between Mueller & Taylor that makes some of the scenes a bit jittery as Mueller moves from anger, bitterness, and hostility emerging from baseless prejudices to an almost adolescent romanticism. Maybe a bit over the top, but that's also a fallibility of the directing and screen writing. Still, her performance, in a difficult role, is laudable.
Sadly, Hollywood didn't call upon Mueller's charming and energetic talents after this movie.
Does this movie meet some important criteria for success?
It has aged well. It is reasonably well-written. It has credible characters that we can love or hate (or both simultaneously). The casting is well orchestrated. There is a dynamic tension between conflicting characters. There are no dull moments -- the story doesn't drag. There are sufficient plot twists to keep the viewer curious for the denouement. There are several very memorable lines worth quoting. It's worth seeing twice to capture its nuances.