Tech experts have commenced their test drives on the Galaxy S4 and the general sentiment is - the Samsung flagship is fairly good but another Android handset, the HTC One, will surely give it some tough moments.

Many were impressed that the GS4 delivers new Smart features, some of which were rollovers from the rousingly successful Galaxy S3, but the overall package seems to fall short of expectations, which are quite high.

It is expected that the GS3 replacement surpass the achievements collected by Samsung last year, among them global sales that so far breached the 40 million mark. Unfortunately, it hard to imagine that the4 GS4 will even replicate such feat, the reviews said.

For Wall Street Journal tech guru Walt Mossberg, the quad-core GS4 (in some markets it would be 8-core on Exynos CPU) is hardly a game changer. He reached that assessment after four days of toying with the Android device.

"While I admire some of its features, overall, it isn't a game-changer ... It's a good phone, just not a great one," said Mr Mossberg.

He added that some of the new functions were rather confusing than amusing.

The Verge concurs, bemoaning that for all the mouth-watering spec bump ups afforded to the new Galaxy premium phone it is both noisy and complicated.

The GS4 could even pass up as a minor update of the GS3, David Pogue of the New York Times observed.

"The Galaxy is still a beautiful, high-horsepower Android phone. But basically, it's an updated Galaxy S3," his review offered.

While the Samsung handset will not disappoint Android fans, something else would easily deliver the goods with a bonus - sturdier body-build. Jessica Dolcourt of CNET pointed to the HTC One, which takes its pride on casing that is composed of an aluminium unibody chassis plus a Corning Gorilla Glass 3 for a reliable screen protection.

HTC's premium the One is the far more impressive phone physically, and has a much fresher interface design to boot," Ms Dolcourt said on her review.

David Pierce of The Verge affirmed that HTC One is the better buy because it "is refined, quiet, comfortable, beautiful, and above all simply pleasant,"

Mr Mossberg argued too that gadget buyers will get more from the One while paying for almost the same price. "The HTC has a handsome, sturdier, aluminium body, dual stereo speakers, an excellent camera, better screen resolution ... and twice the base memory for the same price," he explained.