Deserves better rating (spoilers)
This deserves better than the 5.7 it's getting on IMDb now. I never found it boring. Also, it breaks some stereotypes of the science fiction of the day. The attractive woman scientist isn't rescued by a handsome young man but ends up getting killed by the alien. Also, the alien, while quite nasty, is allowed to leave the earth after finishing his mission.
I mentioned the attractive woman scientist. Actually, that's another point worth discussing. You notice that they didn't try to make her look like a perfect beauty. They left her little facial blemishes. She was intended to be attractive enough to be sought by the alien, but not so attractive that her looks overshadowed her role as a scientist. That's impressive for that time.