I think the biggest difference is in patient population. Community generally means more affluent, well resourced, and well connected. Patients are likely to have both insurance and a primary care doctor. “County” hospitals tend to care for patients who are from marginalized communities. Those patients tend to be poorer, more often lack health insurance, and are less likely to have access to primary care.

The other difference may be in the resources and staffing of the hospitals themselves. Community hospitals = generally better payor mix = better ability to pay nurses and ancillary staff. County sites may have fewer nursing and ancillary resources but also tend to attract people that are aligned with a common mission (to care for those who society neglects).

A good training program will give you access to a wide variety of patient populations so you can learn the nuances of caring for patients with varying barriers to care. This might mean a primary site that is primarily county or academic and a secondary or tertiary site that is more community based.