Most MD schools have teaching hospitals, while most DO schools don't (public DO schools are the notable exceptions). There are many benefits of having an affiliated teaching hospital. First, many teaching hospitals are large, academic, level I/II trauma centres with significant research and clinical opportunities. The quality of the clinical rotations is standardized, and you get more exposure to a wide range of diseases with higher patient flow. You additionally could network with the residency programs at these teaching hospitals to gain an edge for your residency application.