Drop in the uninsured rate

Just by looking at the numbers, it's obvious that the law's single biggest impact is a significant decrease in the uninsured rate.

The uninsured rate has been on a continuous decline since PPACA's implementation, most notably after the individual mandate went into effect in 2014.

The uninsured rate among U.S. adults now sits at 12.3 percent, down marginally from 12.9 percent in the fourth quarter, Gallup most recently reported. One year ago the uninsured rate was 17.1 percent, marking a drop of 5 percent since the individual mandate under the Patient Protection and Affordable Care Act went into effect.

Also read: Top 5 states with the lowest uninsured rate

Gallup pollsters say they expect the uninsured rate to decrease even further, given that the PPACA enrollment deadline — originally slated to end Feb. 15 — had been extended for some and pushed back even further in some areas of the country.

But that's not all. Expect the uninsured rate to drop further in the coming year due to the employer mandate, expanded Medicaid and the increasing fine in 2015 for not having insurance under the law.

Young adult provision

PPACA's provision allowing young adults 26 and under to stay on their parents' coverage was one of the most popular initiatives to come out of the legislation.

Former Florida Gov. Jeb Bush said last week that while he'd like to repeal the entire law, he could support keeping a provision that allows parents to keep their children on their health insurance policies until age 26.

He's not the only GOP supporter of the provision: Republican alternatives to Obamacare drawn up by Sens. Orrin Hatch and Richard Burr and Reps. Fred Upton, John Kline and Paul Ryan include the provision.

One reason for its popularity is likely its effectiveness: According to the Department of Health and Human Services, more than 2 million Americans aged 19-25 gained new coverage because of the under-26 provision. And, according to Gallup numbers, the uninsured rate dropped the most among 18- to 25-year-olds, falling about 6 points from a year ago.

Pre-existing condition coverage

Another hugely popular provision of PPACA, especially among consumers, was the law's promise not to deny consumers coverage based on pre-existing medical conditions. The provision alleviated a big industry problem that long kept certain consumers from getting and keeping coverage.

Insurance giants including Humana and Aetna said in 2012 they would keep that provision, along with others (including the young adult coverage provision), even if the Supreme Court killed PPACA.

The pre-existing coverage provision has generally scored high on public opinion polls, even among people who say they don't like the overall law.

The rise of health exchanges

Despite your feelings on PPACA's HealthCare.gov and the state exchanges, you can't deny that health exchanges have changed the health industry for good.

Health exchanges won't be going away, no matter what happens to the law.

The rise of health care exchanges — in addition to the federal and state exchanges set up by PPACA — of course also includes private exchanges, which have been booming in recent years.

One of the largest private exchanges, Towers Watson, last week said it expects enrollment in its private health insurance exchange to hit 1.2 million this year, a 50 percent increase from 2014.

Last year, consulting firm Accenture projected that by 2018 private exchange enrollment will hit 40 million — or roughly one quarter of all individuals with employment-based coverage.

Medicaid expansion

Of course, Medicaid expansion didn't go as the Obama administration — and the law — originally planned. At first, Medicaid expansion under the law was not optional, but that changed when the Supreme Court ruled as such.

Even with 22 states not participating, enrollment in Medicaid and the Children's Health Insurance Program has grown by nearly 11 million people, a 26 percent increase, since just before the exchanges opened in October 2013.

It's a significant boost and a significant change in coverage.

Of course, the administration still continues to urge other states to jump on the Medicaid expansion bandwagon.

"We remain encouraged by interest from governors from all across the country who understand both the economic benefits of Medicaid expansion and the health and financial security it brings to many individuals," Vikki Wachino, acting director of the Center for Medicaid and CHIP Services, said last week. "If the remaining 22 states expand Medicaid, an additional 6.6 million individuals would be eligible for Medicaid coverage."