Which is more important to admissions officers. . . A good SAT subject test score or a good AP score?
If the college suggests or requires Subject Tests, then those scores are more important. If a college does not suggest/require Subject Tests, neither will move the needle in the admissions process.
It is my understanding that ap tests score are more often used for credit, whereas the subject tests (when required for application) are used to examine proficiency in a subject.