Medicare Advantage Plans —Part C of Medicare, are private plans offered through insurance carriers, that serve as alternatives to the traditional, public program for those that qualify for it — underperform traditional Medicare in one respect: They cost 6 percent more. But they outperform traditional Medicare in another way: They offer higher quality.

http://www.nytimes.com/2014/08/19/upshot/medicare-advantage-is-more-expensive-but-it-may-be-worth-it.html?_r=0&abt=0002&abg=0