Is it a good movie?

It is a very good movie and well worth the time to watch it.
Just saw it on Turner Classic Movies.

Yes, excellent movie. See it.

For another point of view, no, it's a lousy movie. Essentially three people remain in their world, and they just worry about coupling. The dialogue is so terrible in that all three characters go from mock-sophisticated chatter (like children pretending to have a tea party), to arguing while still not really saying anything, and in between that Inger gets a stylish new hairdo.

It's an interesting movie. Mainly because it's obscure, and hasn't been shown much, if at all, on TV for the subsequent 60 years since it's release. This is the first time I've ever heard of it, and I'm 67 years old. Just now viewed it on TCM.

All said and done, it feels like an extended version of a typical doomsday Twilight Zone episode from the same era. Which, I suppose, isn't all bad.

No, it's really not a very good movie. Your average Twilight Zone episode where it's the end of the world is much better. This one is bland and not very well written at all. After watching a film like On the Beach, this film looks very small and the resolution at the end is just silly. 4/10

It's a very good movie, intelligent & thoughtful. Ignore comments about it being dated, and look at it rather as a window into the America of the late 1950s: social, political, cultural. If you weren't a child of school age then, you can't really understand how powerful & overwhelming the prospect of complete & utter nuclear destruction was to the world. And the pettiness & stupidity of many social aspects prevalent then is demonstrated simply by the survivors persisting in them, until they wise up & break every taboo surviving from the dead past.