The Galaxy S4, armed with eye motion control technology that will pause a video when the user looks away, comes with a faster chip and is thinner and lighter than the previous S3 model.
Unveiled last month at New York's Radio City Music Hall, the touchscreen device goes on sale in South Korea on Friday and will roll out globally over the weekend.
The release of the Galaxy S4 comes as Samsung finds itself at something of a crossroads in a market that was once dominated by Apple's iPhone.
After years of following and refining the iPhone's pioneering innovations a strategy that resulted in bitter patent battles with Apple Samsung has dethroned its California-based rival to become the world's top smartphone maker.
With that title has come increasing pressure for Samsung to shed its copycat label and come up with its own game-changing innovations.
"Samsung has entered territory that it hasn't been in before, and sales of the S4 will show if can sustain its newfound status in the market," James Song, analyst at KDB Daewoo Securities, told AFP.
Recent smartphone launches have lost something of the glamour and excitement that surrounded the early iPhone releases, in part because they are seen as offering incremental technology upgrades rather than breaking new ground.
The S4's features include a high-definition, five-inch (12.7-centimeter) screen, enhanced picture-taking capabilities and the capacity to translate to and from nine languages.
Its release has been preceded by a massive promotional campaign -- from the glitzy launch in New York to lighting up the sails of Sydney's iconic opera house on Tuesday night with images shot by ordinary Australians.
Samsung -- the world's largest technology firm by value and also the top handset maker -- has boasted stellar sales growth, setting new records for operating profit in every single quarter of last year.
First quarter results due Friday are expected to show a 53 percent surge in operating profit from a year ago to 8.7 trillion won ($7.7 billion), largely fuelled by smartphone sales.
Samsung is estimated to have shipped 65 million smartphones globally in the first three months of 2013, for a market share of around 30 percent, according to Taiwanese analyst firm DRAMeXchange.
Apple by contrast, reported Tuesday that its quarterly profit had dipped for the first time in nearly a decade, with DRAMeXchange estimating its iPhone shipments at 37.5 million units for a 15.3 percent market share.
But Apple's iPhone commands a profit margin double that of Samsung's smartphone stable which holds a much wider range of devices for both low- and high-end buyers.
"Samsung still has a very long way to establish itself as a leader, not a chaser, considering it has never had a genius in innovation like Steve Jobs," said Song.
"But Jobs is no longer at Apple either and the company is struggling. That may help Samsung earn some time to come up with ways to become a market leader in every sense," he added.
J.K. Shin, the head of Samsung's mobile unit, said verdicts from global wireless operators to the Galaxy S4 had been "far more positive" than with previous models and predicted of a "good result" ahead.
More than 41 million units of the Galaxy S3 have been sold globally since its release last May, while the first and second editions racked up sales of 25 million and 40 million respectively.
Song said the S4 had the potential to reach the 80 million sales mark by taking advantage of Apple's recent problems with supply chain disruption.
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