It's always difficult to offer advice based only on the title of the program.
Presumably, the mathematical physics degree is the same as the standard physics degree, but with more required courses in mathematics. Or do those replace some of the standard physics degree courses? Do you have less flexibility with elective courses? Is that important to you?
One thing that can help you make this kind of decision is to go through your course catalogue in detail and choose the courses that you really want to take during your degree. And then base your decision on which program lines up best with your most desired courses. As you do this, make sure to have some kind of a plan for what happens if graduate school doesn't work out.