Samsung's most advanced smartphone to date has gone on sale and is expected to give the electronics giant another boost in its battle with Apple.
The South Korean company's Galaxy S4 was unveiled to much fanfare at a theatrical US launch last month and is said to pose the greatest threat yet to the iPhone.
Industry experts have already lavished praise on the device which allows users to control the screen using their eyes.
Analysts predict it could even tip the balance in favour of the South Korean firm as it wrestles with Apple for top spot in the smartphone market.
Stuart Miles, founder of technology and gadget site Pocket-lint, said the Galaxy S4 was likely to become an "incredibly popular phone". "I think sales of the SGS4 will do well as customers are keen to get the latest Android flagship and carriers are keen to sell it," he said.
Samsung is said to be expecting sales of its new handsets to be as high as 10 million per month, largely driven by its new features. It said there had already been "unprecedented demand" for the phone in the UK.
Slimmer and stronger than its predecessor, the S4 weighs 130g and is 7.9mm thick, while its AMOLED technology means the screen has a resolution of 441 pixels per inch. Among its most heavily emphasised features at its launch was its remote technology which allows users to control functions without touching the screen. The "smart scroll" function enables the S4 to detect the movements of the eyes and wrist.
Ernest Doku, telecoms expert at uSwitch.com, predicted the S4 would see a good take-up but said Samsung was still some way from creating the scenes witnessed outside Apple stores when a new iPhone goes on sale. "Hype surrounding the launch of Samsung's feature-packed S4 has been phenomenal," he said. "Only Apple has managed to pull off anything close to such a frenzy in recent memory."
He added: "Nevertheless, given its affordable pricing and current popularity of the Samsung brand, expect the Galaxy S4 to be fully poised to take on the behemoth that is Apple - our data has it placed as the fifth most popular handset in the UK based on pre-order availability alone."
The handset hit stores just a day after Samsung announced a 41% leap in earnings in the first quarter of this year and in the same week that Apple reported its first annual slide in profits in a decade.