The Galaxy S5, the latest version of Samsung Electronic's flagship Galaxy smartphone, went on sale worldwide April 11. The phone is expected to boost Samsung's sagging profit margins as growth in smartphone sales slows worldwide.

In a sign of the stern market challenges facing Samsung, the Galaxy S5 was priced lower at its commercial launch than the previous S4 model. Research firm IDC believes the average selling price of smartphones will fall to $265 globally by 2017 from $337 in 2013 and $387 in 2012. 

The smartphone sales slowdown is particularly acute in mature markets like North America and Europe. Analysts said the smartphone markets in these two vital locations is nearing saturation.

Reviews of the Galaxy S5 mostly conclude it is one of the best high-end smartphones on the market. There is, however, a general consensus that the S5 isn't sufficiently impressive enough to differentiate it from its predecessors and competitors.

In other words, the "Wow!" factor is ominously absent. Probably the outstanding feature of the Galaxy S5 is its waterproof covering, which the venerable Wall Street Journal pooh-pooed.

Samsung's mobile unit has been the driving force behind the Samsung group's record profits in recent years. Samsung made more than 30 percent of all smartphones sold in the world in 2013, nearly twice the number of its arch-rival, Apple, Inc.

Samsung is also under pressure to set aside more cash for legal bills due to its unrelenting patent battles against Apple. The two are facing off in patent lawsuits in San Francisco and several other countries involving design and technologies on their smartphones and tablet computers.