I know a family in my neighbourhood who faced that choice. The family has three famous sons.
Both 1st and 2nd sons had MIT admission and CMU full ride.
The oldest one went to CMU full-ride; second one went to MIT; third one is still in high school (most likely will get in MIT and CMU)
I don't know the family well enough to ask them why the second one decided to go to MIT. Maybe they consider MIT worth $300K after the oldest son went to CMU. Maybe it is the second son's choice. Not depends on the merit of the schools.