Apple Inc's newest iPhone left Wall Street and fans wishing for more than a souped-up version of last year's device, at a time when rival smartphone makers are nipping at its heels.

At his first major product launch since being crowned CEO, Tim Cook ceded the critical iPhone presentation to another executive, and failed to generate the same level of excitement and buzz that predecessor Steve Jobs was famous for.

The new iPhone 4S is identical in form to the previous model, disappointing fans who had hoped for a thinner, bigger-screened design. Apple's shares fell as much as 5 percent, before recovering with the broader market to close down 0.6 percent.

But analysts say the new device sported some new features, such as voice commands, to draw in consumers and is still going to be a big draw this holiday season, particularly as the phone is now available on Sprint's network in addition to AT&T and Verizon Wireless.

It remains to be seen whether the iPhone 4S can stem market share gains by phones running Google Inc's Android software. Samsung Electronics, notably, is growing global shipments several times faster than Apple and is now estimated at within a hair's breadth of catching up in worldwide market share.

It's been 16 months and all you've got is an A5 processor in the existing iPhone 4, BGC Partners' analyst Colin Gillis said of the new Apple phone. It's a mild disappointment, but they're still going to be selling millions of units.

The iPhone 4S's voice commands -- for sending messages, searching for stock prices and other applications -- caught the attention of several analysts who argued it could profoundly change the user experience.

Known as Siri, the technology already exists on Android but experts say Apple's integration was more fluid -- a hallmark of the company.

Whether such high-tech wizardry is enough to make the iPhone 4S a must-have in consumers' eyes and set it apart from the competition, remains to be seen.

It's not clear that Siri is sufficient to make or break a purchase decision, said John Jackson, an analyst at CCS Insight. It's a better mousetrap. History tells us users don't use this technology in great numbers.