Though the Affordable Care Act, usually called Obamacare, has been law now for long enough for the Republicans to have failed at repealing it about a jillion times, the sun continues to rise each morning in the east before setting in the west. While the laws of nature remain operative, the percentage of Americans without health insurance is moving in the right direction--from over 20% when the new coverage provisions took effect, to 17.7% in the first quarter of 2014, to 14.9% in the third quarter of 2014, to 13.2% currently. The data points are from the Gallup-Healthways Well-Being Index and may be viewed here. Another key finding: since the law took effect, about 16.4 million previously uninsured Americans have acquired coverage, and gains are particularly strong in states that allow for the expansion of Medicaid.
I'm not sure what would have to happen for the law's opponents to allow that maybe they, um, exaggerated.