The quick answer to this is yes! Some students do comparatively better on one test than the other and schools accept either one. The only school I know of that accepts only the ACT is BYU. Most high school students on the east and west coasts take the SAT and the midwestern students take the ACT, but many students choose to take both.
If students are unsure which test they will perform better on, they can take a practice test of each and score them. They would need to time themselves and take a real test. They will find a complete real test of each at their high schools, usually in the counseling office.