​Is anyone happy with Obamacare's exchanges?

For naysayers of the Affordable Care Act, the fall may be providing them with a "told you so" moment.

The exchanges set up by the health care law were designed to bring choice and transparency to the process of buying health care insurance for Americans who need individual plans. Part of the idea was that the exchanges would sign up young Americans, and those healthier types would help even out the high treatment costs for the exchanges' sickest patients.

Reality, however, has given those plans a more sober diagnosis. UnitedHealth Group (UNH) on Thursday said it has scaled back marketing for Obamacare exchange products, and may even leave the marketplaces altogether. Meanwhile, health co-operatives that were formed to provide insurance through the exchanges are failing right and left, leaving at least 500,000 people without insurance, according to The Wall Street Journal. To top that off, some consumers are facing big jumps in insurance premiums bought through the exchanges this year, leaving many feeling sour.

It's fair to ask whether anyone is happy these days with the Obamacare exchanges.

"We cannot sustain these losses," UnitedHealth chief executive officer Stephen Hemsley said on a conference call. "We can't really subsidize a marketplace that doesn't appear at the moment to be sustaining itself."

Some opponents of Obamacare are claiming UnitedHealth's financial issues with the exchanges proves that the health care law isn't working, with conservative group FreedomWorks CEO Adam Brandon noting in a statement, "UnitedHealth's decision to [scale back] confirms that we were right."

Not so fast, said Jeff Smedsrud, CEO of HealthCare.com, which runs a comparison-search service for finding health insurance coverage. The ACA has delivered more transparency to the health care market, more choice for consumers, and has barred insurers from denying insurance coverage to patients, he said. While those are all good things, the market is still evolving, and there are going to be bumps along the way, he added.

"The idea that consumers can move around is a good thing," he said. "It proves that it's a marketplace, and sometimes marketplaces are messy."

UnitedHealth, the biggest U.S. health insurer, blamed "tempered" participation in its exchanges during this month's open enrollment period. The company didn't disclose the reason why fewer people are signing up for its plans through the exchanges, but it's possible some consumers are feeling sticker shock from UnitedHealth's rate hikes.

Plans sold through Florida's exchange by UnitedHealth are set to rise an average of 18 percent, according to CNN Money.

Higher rates across the exchanges "are making 2016 more interesting than 2015," Smedsrud said. "That's causing people to shop around, and carriers are spending more marketing dollars to get a customer who they thought would be with them for a year, and six months later is moving to another plan."

At the same time, UnitedHealth complained about another issue: "more difficulties with our own claims experience," according to a statement from Hemsley.

While the company didn't clarify what it meant by "difficulties," it's clear that UnitedHealth isn't winning over its current customer base. The insurer sank near the bottom of U.S. health insurers in the American Customer Satisfaction Index's most recent poll on health-care insurers, dropping 8 percent in consumer satisfaction. Several websites exist dedicated to logging complaints about UnitedHealth. Consumers have posted almost 350 ratings for UnitedHealth at ConsumerAffairs, a consumer advocacy group. Only two of the ratings give the company five stars, while 332 customers provide the lowest rating of one star.

Given UnitedHealth's plunging customer-satisfaction ratings and price hikes, it begs the question of whether the health insurer's problems are starting closer to home.