About 5 years ago I took a health care policy class and we looked into this. In terms of outcomes, the U.S. was thoroughly mediocre, except for breast cancer and diabetes, where we were at the head of the pack (in terms of treatment) but not, say, better by a multiple.

The fact that the US has many leading medical research institutions is often abused to argue that we have the best care, but it's largely irrelevant for the overwhelming majority of delivered care and even more irrelevant for outcomes.