Apple iPhone 6, iPhone 6 Plus earn positive reviews

Bigger is better and Apple Inc has finally realized that and given iPhone users a product that may be low on novelty but high on improvements, reviewers wrote.

Most reviewers say that the iPhone 6 is the best smartphone available or "ever made", while the 5.5-inch iPhone 6 Plus has been described as a "phablet" that will give competition to Samsung Electronics Co Ltd's Galaxy S line of 'big' Android phones.

"I think it's a terrific phone. In my view, it's the best smartphone on the market, when you combine its hardware, all-new operating system, and the Apple ecosystem whose doors it opens," Walt Mossberg wrote of the 4.7-inch iPhone 6 in the tech blog Re/code.

• See how the iPhone 6 and iPhone 6 Plus stack up against other smartphones
• Apple Watch, iPhone 6, Apple Pay: A closer look

Geoffrey Fowler, who reviewed the phones for the Wall Street Journal, said Apple has "successfully addressed its size deficiency."

Mossberg said the increase in the screen size is a "catch-up" feature. But it is seen as a welcome change by Fowler, who said the iPhone "felt stuck in a bygone era called 2012" before the launch of the bigger phones.

New York Times reviewer Molly Wood appreciated the new "thinner, flatter and more rounded shapes" of both the phones. But she pointed out that the sleek look comes at the cost of the phones feeling "slippery".

The improvements made to the operating system the iOS 8 software, and that to the camera were given a thumbs up by reviewers across the board. However, most believed that Apple could have done more to enhance the battery life of the phones.

• Apple's iOS 8: It's delivery day for new mobile operating system

• 8 biggest changes in iOS 8

Joshua Topolsky, who reviewed the phones for Bloomberg, said they were faster than their predecessors.

"Apple will tell you that these are the fastest mobile devices it's ever made, and it wouldn't be lying. These phones scream," Topolsky wrote.

Tech blog The Verge's David Pierce said the new iPhone's camera was its standout feature, making it the "best smartphone on the planet". The camera now allows faster image focusing and slow-motion video recording.

The new iPhone 6 goes on sale on Sept. 19 in Canada, the U.S., and several other countries.

Apple said it received a record 4 million first-day pre-orders for the new phones, double the number for the iPhone 5 two years ago.

Apple shares were trading up 0.6 per cent at $101.46 in morning trading on the Nasdaq.