The deep political divisions the law has engendered — just 38 percent of Americans view it favorably, according to survey findings released this week by the Kaiser Family Foundation — make assessing it a complex task. The evidence remains largely anecdotal; for every satisfied supporter, it seems, there is a disgruntled opponent.

Wayne Buchholz, a 47-year-old rancher in Rhame, N.D., saw his high-deductible insurance policy canceled; he bought a new policy for his family, he said, but the premium doubled, to $800 a month, and the $12,000 annual deductible is similar to what it was before.

“Liberals in Washington think that we are not smart enough to make our own decisions, that I’m too stupid to decide what’s good for me,” Mr. Buchholz said. “In the past, I deliberately chose to have a higher deductible and a lower premium because I believe that insurance should be there for costs we cannot afford. Now I have a high premium and a high deductible, and virtually no choice.”

But across the country in Baltimore, Theresa Thomas, 52, the director of a drug abuse treatment center, waited more than two hours at a recent health care enrollment fair to sign up for coverage for herself. She picked a plan that offered medical and dental coverage and was thrilled with her $179 a month premium, saying, “I’m walking out of here with a smile.”

The Supreme Court’s 2012 decision to allow states to opt out of Medicaid expansion, and the decision by roughly three dozen states not to establish their own exchanges, have created cross-border disparities in coverage. Technical troubles with the federal HealthCare.gov website have depressed signups in many states that rely on it. The political climate in some states also has helped determine whether people enroll.

Missouri and Texas, where opposition to the law is strong, are among states that have enacted tough restrictions on who can serve as “navigators,” or “certified assistance counselors” to guide consumers through the enrollment process. That has frustrated Mona Walls, who runs a small team of enrollment counselors in rural southeastern Missouri.