The tech giant has not yet issued full review handsets, but journalists got some hands-on time with the iPhone 5 at the launch event on Wednesday (September 12).
TechCrunch's John Biggs said that thanks to the new A6 processor in the iPhone 5, the handset is "far speedier" than its predecessor, the iPhone 4S.
"Maps and photos flew by and the various apps popped up in a few seconds," he noted.
But he said that the "real draw" is the Retina screen, which moves up to 4 inches on the diagonal in the new phone from 3.5 inches in past iPhones.
Whilst Biggs said that he is reserving judgement on how the screen performs in "real-world conditions", he feels that it could offer "the sweet spot between monsters like the Galaxy S3 and the arguably bordering-on-too-small (at this point) iPhone 4".
Copyright: AppleHe also praised the build quality in the iPhone 5, noting that the solid aluminium is "quite unique and quite solid", which will hopefully reduce some of the damage should the phone be dropped.
"We'll know far more about these phones when we get to really use them later this month but until then I can report that this is a solid and interesting improvement to a solid and interesting phone," he wrote.
"Is it a blockbuster launch? Probably not, but it is an interstitial launch that allows Apple to update the screen size and dock connector while still hiding some tricks up its sleeve."
TechRadar's Patrick Goss noted that the new iPhone may not have enough under the hood to persuade iPhone 4S owners to upgrade, but it could convince legacy iPhone 4 users to take the plunge.
"You get the impression that this is goal number one for the company," he wrote in a hands-on piece.
However, Goss said that the decision by Apple not to include a chip for Near Field Communications (NFC) in the iPhone 5 is a "real misstep".
NFC is a new technology that enables users to send information between designated points with just a 'tap'. It is often used for wireless payments in shops, or for 'check-in' at transport locations.
Apple announced a new Passbook application coming to the iOS 6 operating system that will run on the iPhone 5, enabling people to keep all their digital tickets, offers and store cards in one place. But it did not include a full-blown NFC chip in the handset.
"Given the level of hype around the Apple iPhone 5, it's almost inevitable that the phone itself ends up feeling a little underwhelming when it is launched, but Apple is a past master at ticking the boxes, and giving its growing legion of fans enough to justify an upgrade," said Goss.
"Is it going to sell like hot cakes? Of course. Will it send shock waves shuddering through the tech world and turn competitors back to their drawing boards? No.
"Not having NFC is a real misstep, as it would have made the Passbook application in iOS 6 much better (and in keeping with its Android and Windows Phone rivals) and it certainly would have been nice to see something remarkable in addition to some nice, but not startling, upgrades.
"But, in truth, Apple will be well aware that it doesn't need to reinvent the wheel to succeed and, in this case, it has yet again provided a fine phone that will keep it battling at the top of the charts for another year."
> Apple iPhone 5: Has Apple lost its cool?
> Apple iPhone 5: What the public are saying
Writing in The New York Times, David Pogue gave a pretty positive initial impression, praising the design of the handset and the improvements in the 8MP iSight camera, including the "crazy good" Panorama shots.
However, he joined others in expressing concern at the new smaller Lightning dock connector fitted to the iPhone 5, replacing the 30-pin port that Apple has used since 2003.
"I'll grudgingly admit that the Lightning connector is a great design: it clicks nicely into place, but it can be yanked out quickly. It goes in either way - there's no 'right side up', as there was with the old connector. And it's tiny, which is Apple's point," he wrote.
"Still, think of all those charging cables, docks, chargers, car adapters, hotel-room alarm clocks, speakers and accessories - hundreds of millions of gadgets that will no longer fit the iPhone.
"Apple will sell two adapters, a simple plug adapter for $30 or one with a six-inch cable for $40 (£25 and £30 in the UK) to accommodate accessories that can't handle the plug adapter. That's way, way too expensive.
"These adapters should not be a profit centre for Apple; they should be a gesture of kindness to those of us who've bought accessories based on the old connector. There's going to be a lot of grumpiness in iPhoneland, starting with me."
Engadget's Dan Cooper said that he was not "underwhelmed" by the hardware in the iPhone 5, but was hoping for a more "revolutionary leap that was a little more future-proof" from Apple.
The base 16GB iPhone 5 will cost £529 SIM-free, rising to £699 for the 64GB model, although it will be discounted on mobile contracts.
Cooper said that he will pre-order the iPhone, but he hopes that there will not be anything significantly better coming from Apple in the near future.
"When I give in and wind up buying this, I'll be spending a fraught few months hoping they don't build anything too magical into iOS 7 since I'm reasonably sure my bank balance can't take it," he said.
However, his colleague Darren Murph added that the range of new features in the iPhone 5, such as the better camera, along with the addition of Long Term Evolution connectivity, means that it has enough in the locker to persuade him to upgrade.
"Look, there wasn't a lot that surprised me at today's event, but I'm pre-ordering an iPhone 5. I want the LTE radio. I want the extra pixels. I want the new camera," he said.
"But most of all, Apple made it really easy for me to justify using my AT&T upgrade on this: it's a flagship, 4G-enabled phone that's launching at $100 less than many of the Android-based flagships.
"Sure, I could enjoy most of the iOS 6 spoils on my existing iPhone, but the new one is faster, sleeker and just sexier. Do I need it? No. But as a technology lover, I really am impressed with the design."
For a slightly alternative viewpoint, Ricky Gervais tweeted the following: "iPhones are Barbie Dolls for grown men. You carry them round, dress them up in little outfits, accessorise, & get a new one every year."