Donald Berwick is a highly respected expert on health care who was president Obama’s nominee to head the Center for Medicare and Medicaid Services. So of course he was opposed by the Republicans who are determined to block anything that might benefit people under the act. He was forced to serve for just a limited time by means of a recess appointment and has now stepped down from that post.
Chris Hayes had an interview with him that I highly recommended watching, especially his explanation about the important aspects of the Affordable Care Act. That begins at the 9:00 minute mark.