Reception for all carriers has been steadily improving over the last few years and should continue to do so.
Verizon service is vastly superior to all other carriers on campus. Verizon currently is the only carrier on campus that supports cell-over-WiFi calling. The phone must be capable of that feature, not all are.
AT&T has horrible coverage on campus. The others a mixed bag of not-as-good-as Verizon.