Experts may be lowering projections for Apple's iPhone 5 for next year based on the volume already sold and unprecedented competition, and Samsung's Galaxy S III might be outselling in the United Kingdom, but there's some encouraging news from one research source that Apple's smartphone share is in solid shape.

Big Jump

London-based Kantar Worldpanel, which gathers market information through consumer panels, says Apple has achieved its highest-ever share in the U.S. with 53.3 percent in the 12 weeks ending Nov. 25, due to iPhone 5 sales. The picture is less rosy in Europe, though, with Google's Android bumping its share from 51 percent a year ago to 61 percent.

"Apple has reached a major milestone in the U.S. by passing the 50 percent share mark for the first time, with further gains expected to be made during December," said Dominic Sunnebo, global consumer insight director at Kantar Worldpanel ComTech.

Apple nemesis and court sparring partner Samsung is still the reigning smartphone maker across the big five most important countries, with 44.3 percent share in the latest 12 weeks, far exceeding Apple's 25.3 percent. Also-rans HTC, Sony and Nokia are jockeying for the third-place spot.

"Although Windows sales in the U.S. remain subdued, Nokia is managing to claw back some of its share in Great Britain through keenly priced Lumia 800 and 610 prepay deals," Sunnebo said in a statement. "The next period will prove crucial in revealing initial consumer reactions to the Nokia 920 and HTC Windows 8X devices."

Kantar WorldPanel found that Nokia's devices aren't appealing to a younger demographic, though. In the past six months, only 28 percent of Nokia Lumia 800 sales have come from people under 35, compared with 42 percent of all smartphone sales.

Wireless expert Gerry Purdy of MobileTrax sees Apple facing perhaps its most challenging year yet.

"They owned the market and created it, but Android now has a larger market share worldwide," Purdy told us.

Up in the air is the effect of the Nokia-Microsoft partnership and the revamped BlackBerry operating system coming soon. "Will it be cool or ho-hum?" wondered Purdy of the next generation of devices from the struggling Canadian Research In Motion.

Needs Its Own 'Big Thing'

He noted that Samsung's marketing pitch for its Galaxy devices seems to resonate: The next big thing is already here.

"The screen size is bigger and it has [near-field communication] which the iPhone doesn't have," Purdy said, meaning that the iPhone can no longer claim to be at the cusp of innovation. The company then needs to find a software solution or another form of differentiation.

Kantar WorldPanel sees smartphone penetration in Great Britain reaching 60 percent during the research period, or 83 percent of all mobile phone sales during that time.