Rand Paul has been instrumental in killing FAKE obamacare “repeal and replace” bills, none of which actually would do that. In general, the Paul Ryan derived bills made things far worse, driving up costs particularly for the various classes of Trump supporters. Rand Paul has also been instrumental in working with Trump to do via executive action what Congress has refused to do.
On the other hand, those other three have worked very hard to assure that obamacare continue like it has.
Rand Paul is also a medical doctor who knows better than anyone else in Washington how badly our fouled-up health care system works for the people who matter most in health care: the patient and the doctor.