"Europe drove a lot of the growth a couple years ago, but that resulted in overinvestment and now growth is slow there," Carey said. "The growth potential appears to be in China and the U.S.," he said, adding that Japan, the Middle East and Latin America also show strong potential.
Intense competition has forced reductions in manufacturing costs, and that is ultimately good for the industry, Carey said. "Panel [makers] come to us to help them optimize production. I'm optimistic prices will continue to decline."
As manufacturing cost reductions reach their limits, the focus will shift to "soft costs": installation, permitting, marketing and financing. Such costs in the U.S. are 40 percent more than in Germany, Waserstein said, because companies there are better at minimizing them.
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Tom Burton, founder of the energy and clean technology practice at the law firm Mintz Levin, likes panel maker First Solar for its competitive advantages.
"It's the gold standard—they've figured it out," he said, citing scalability, innovation, and vertical integration. Shares are up 26 percent this year, though 31 percent off a June peak.
A major driver of U.S. residential demand is the financing packages that make solar panel installation more feasible for homeowners, Burton said.
But Waserstein said that a lot of cost streamlining remains to be done.
Economically battered European countries aren't as well-positioned as they have been to support solar energy development and adoption. Meanwhile, China is showing a willingness to subsidize projects, which could help boost demand.
In the U.S., the Solar Investment Tax Credit—a 30 percent credit for residential and commercial solar systems—will run through 2016.
"The long-term prospects [for solar] are very strong," said Carey of PricewaterhouseCoopers, "and the overall trajectory is upward."
—By CNBC's Matt Twomey. Follow him on Twitter