ACT or SAT: Which fits better if pacing is my issue?

I'm in a bit of a dilemma about whether to take the ACT or the SAT. My main concern is timing—I'm always feeling rushed on the ACT math section. Meanwhile, I find myself overthinking the tougher questions on the SAT. For those who have tried both exams, did your decision come down to the structure and pacing of the test or more about the content itself?