Apple's new CEO Tim Cook had big shoes to fill after Steve Jobs' departure last August, but yesterday's iPhone announcement provided the executive a chance to step into the limelight. Contrary to what many were hoping, however, the iPhone 5 was a no-show at the event, so no bigger screen and no slimmer profile. Instead, the iPhone 4S is an incremental update to the iPhone 4 that keeps the same external design with new hardware under the hood.

This is comparable to what we saw when the iPhone 3G was succeeded by the 3GS. Apple has included some worthy upgrades to the venerable iPhone 4 that will go a long way towards luring many new buyers as well as upgraders. If you're on the fence regarding yesterday's update and what it means for iPhone users, here's what you need to know.

Hardware

The iPhone 4S looks identical to last year's model but comes in a new 64GB flavor and upgrades the camera to include an 8-megapixel sensor with improved low-light performance and 1080p video capture. "To many customers this will be the best still camera they've ever owned and the best video cameras they've ever owned," said Phil Schiller during the presentation. There's better white balance, better color accuracy, face recognition, and faster photo capturing.

In terms of performance the new iPhone is reportedly up to 2x faster than its predecessor. The dual-core graphics engine is said to be seven times faster than the iPhone 4's. Despite the faster processor battery life was also slightly improved. For CDMA users who travel frequently, the support for GSM global roaming should be a pretty big deal, too.

The new iPhone 4S is also capable of running on faster HSPA+ networks, reaching theoretical download speeds of up to 14.4Mbps versus 7.2Mbps on the previous model. Apple says that they have changed the antenna system, presumably to solve the signal attenuation problem. The side-by-side comparison below details what's changed in the new iPhone 4S:

  iPhone 4S iPhone 4
Price on contract $199 16GB, $299 32GB, $399 64GB $99 8GB
Carrier AT&T, Verizon, Sprint AT&T, Verizon, Sprint
Processor 1GHz dual-core A5 1GHz single-core A4
Display 3.5-inch IPS 960 x 640 3.5-inch IPS 960 x 640
Rear camera 8 megapixel AF with flash
and f/2.4 aperture
5 megapixel AF with flash
Front camera VGA VGA
Video recording 1080p at 30fps 720p at 30fps
Network CDMA / EV-DO Rev. A and
GSM / 14.4 HSPA
CDMA / EV-DO Rev. A or
GSM / 14.4 HSPA
Siri voice assistant Yes No
Battery life 8 hours 3G talk time
6 hours data on 3G
9 hours data on Wi-Fi
40 hours audio 10 hours video
7 hours 3G talk time
6 hours data on 3G
10 hours data on Wi-Fi
40 hours audio 10 hours video
Weight 140g 137g
Dimensions 115.2 x 58.6 x 9.3mm 115.2 x 58.6 x 9.3mm
iOS 5: Major features rundown

The next update to Apple's iOS is set to arrive on October 12 and will run on iPhone 3GS or newer models, as well as both iPads and the third- and fourth-generation iPod touch. It will be available as a free download and should bring more than 200 new features to Apple's devices – many of which we covered here. Apple highlighted a bunch of the most important ones during yesterday's event.

These included a revamped notifications system (very Android-like), an iOS messaging service called iMessage with features like delivery and read receipts (BBM for iOS, basically), location-aware reminders, Twitter integration across the operating system, Newsstand for periodicals and magazines, a new camera app that's easier to access and can use the phone's volume button as the shutter button, a revamped Safari browser with support for tabbed browsing (it was about time) and a "read later" feature, a new Mail app and, at long last, PC-free setup and synchronization.

There's a separate service called iCloud that will work across Mac products and facilitates the automatic synchronization of your contacts, calendar, mail, documents, photos, music, books, apps and backups. Apple's iCloud provides 5GB of free storage and can be paired with a $24.95 per year music locker service called iTunes Match.

These are all features that were previously detailed by Apple during its WWDC in June, but the company saved a few surprises. The first and least interesting of the bunch is a new app called Cards that lets you create actual greeting cards on iOS. Users can select from 21 different designs. Once you've created a card, Apple will print it out and send them anywhere in the U.S. through USPS for $3 per card, or anywhere in the world for $5. Watch out Hallmark!

Another new feature is Find my Friends, which is sort of like Google's Latitude but with better privacy controls. With Find My Friends you can choose to permanently or temporarily share your location with people, set parental controls, or go off the grid with the flip of a switch. It's included free in iCloud and integrates with Contacts and Maps.

Last but certainly not least, Apple is also including Siri in the iPhone 4S, which will only run in this model (and presumably the iPad 2 since it uses the same A5 chip). Described as an intelligent assistant that helps you get things done just by asking in natural language, Siri lets you use your voice to send messages, schedule meetings, place phone calls, and more. This is the iPhone 4S' standout feature and promises to change how users interact with their phones.

It actually interprets what you are saying rather than just respond to commands. For example, in a demo of Siri, Apple's Scott Forstall wanted to create a reminder to call his wife after leaving work. He said, "Remind me to call my wife when I leave work." Siri asked to confirm the reminder, already knew who his wife was and set up a geofence around his work. When he leaves that perimeter, Siri will remind him to make the call.

Don't miss the video above for more examples. If it works that well this could be a really interesting addition for the iPhone. Siri will only support English, French and German initially, but Apple says it will expand its features eventually.

Carriers and availability

Pre-orders start October 7 and availability in the US, Canada, Australia, the UK, France and Germany will be on October 14. Later in the month 22 more countries will get the 4S, on October 28, with a total of 70 countries getting the device by the end of the year. The phone will be available on AT&T, Verizon Wireless and Sprint in the U.S.

This is the first time Sprint customers will get a chance to buy Apple's popular smartphone – T-Mobile users are still out of luck. Verizon and Sprint's iPhone 4S still won't do voice and data simultaneously, that remains an AT&T-only perk. On the other hand, neither Verizon nor AT&T offer unlimited data plans. There are rumors that Sprint will offer the phone with unlimited data service and plans to distinguish itself from the competition but this hasn't been confirmed yet.

Is it worth upgrading to?

That depends on how much weight you put on the faster processor and improved camera. For many iPhone 4 owners it probably won't be worth the trouble after upgrading to iOS 5 and giving their smartphone a new lease of life. Its A4 processor will likely handle the operating system with relative ease considering even the 3GS can run iOS 5, and while the upgraded camera looks really powerful I wouldn't base my purchase decision solely on this feature.

The Siri voice assistant will also be exclusive to the 4S and may be able to lure quite a few if only for the novelty factor. The technology is certainly impressive if it ends up working as smoothly as shown in the demos. Realistically, though, Siri will likely come handy in some scenarios but most people will still rely primarily on touch to interact with their phones.

In short, iPhone 4 users don't have a lot of reasons for upgrading their device yet – especially after their phones gain 200+ features with iOS 5. On the other hand, those coming from older devices are in for a nice performance bump along a taste of the future of iOS with Siri.

How the iPhone 4S stacks up against the competition

Below is a spec-by-spec comparison with other top phones on the market, including the rumored Nexus Prime that is set to arrive sometime in the fall running Android Ice Cream Sandwich. We've skipped Windows Phone 7 devices as most are over a year old and we'd rather wait for the new hardware coming out soon.

As you can see this time Apple is just slightly ahead of the competition in some areas and falling behind or catching up in others. With Android (and soon enough Windows Phone 7) you have more display size options, great cameras, room for storage expansion, better connectivity options, and many of the phones available today look and feel just as sleek and well-designed as Apple devices. However, saying one phone is better than another based purely on hardware specifications or performance is not the best approach – perhaps even a little shortsighted.

In the end it all boils down to your budget and expected core functionalities or strengths in a specific phone (lightweight, larger screen, gaming oriented, text heavy input, etc). Apple's iOS 5 brings some important new features and services like iCloud and iTunes Match are going to further improve the experience of owning one of these devices. Apple's App Store remains unmatched in terms of available applications and the catalog is much more organized. The new Siri feature also emerges as a more polished version of Android's Voice Actions – though we'll need some hands on time with it before any conclusions can be drawn about how useful it really is.

  Apple iPhone 4S Motorola Droid Bionic Samsung Galaxy S II HTC Sensation 4G T-Mobile G2X Motorola Photon 4G Apple iPhone 4 Samsung Nexus Prime
Price -- $590 $550 $490 $360 $550 $549 --
Price on contract $199-$399 $150-$220 $100-$150 $200 $150 $100-$180 $99 TBA
Availability AT&T, Verizon, Sprint Verizon AT&T, Sprint T-Mobile T-Mobile Sprint AT&T, Verizon (soon on Sprint) ???
TS Metascore N/A 78 N/A | 84 N/A 88 78 89 N/A
Processor 1GHz Apple A5 1GHz TI OMAP 4430 1.2GHz Samsung Exynos GT-I9100 1.2GHz Qualcomm Snapdragon MSM8260 1GHz Nvidia Tegra 250 1GHz Nvidia Tegra 250 1GHz Apple A4 1.5GHz Samsung Exynos
Display 3.5" (640x960) 4.3" (960x540) 4.27" (800x480) 4.3" (540x960) 4.0" (480x800) 4.3" (960x540) 3.5" (640x960) 4.65" (1280x720)
Memory 512MB 1GB 1GB 768MB 512MB 1GB 512MB 1GB
Internal Storage 16GB-64GB 16GB 16GB 4GB (1GB accessible) 8GB 16GB 8GB 16GB
External Storage No 32GB microSD 32GB microSD 32GB microSD 32GB microSD 32GB microSD No 32GB microSD
Front Cam VGA 0.3MP 2MP 0.3MP 1.3MP 0.3MP VGA ???
Rear Cam 8MP 8MP 8MP 8MP 8MP 8MP 5MP 8MP
USB No Yes Yes Yes Yes Yes No ???
HDMI No Yes Yes Via MHL Yes Yes No ???
Wireless Connectivity Wi-Fi, Bluetooth 4.0 Wi-Fi, Bluetooth 2.1 Wi-Fi, Bluetooth 3.0, NFC Wi-Fi, Bluetooth 3.0 Wi-Fi, Bluetooth 2.1 Wi-Fi, Bluetooth 2.1 Wi-Fi, Bluetooth 2.1 ???
Talk / Standby Time 8 hours, 8.3 days 10.8 hours / 8.3 days 9 hours / 12.5 days 8 hours / 14.5 days 7.8 hours / 16.5 days 10 hours / 8.3 days 7 hours / 12.5 days ???
OS iOS 5 Android 2.3.4 Android 2.3.4 Android 2.3.4 Android 2.3.3 Android 2.3.4 iOS 4/5 --
Dimensions (inches) 4.50 x 2.31 x 0.37 5.01 x 2.63 x 0.42 4.93 x 2.60 x 0.33 4.96 x 2.57 x 0.44 4.88 x 2.49 x 0.43 5.00 x 2.63 x 0.48 4.50 x 2.31 x 0.37 0.34 thick
Weight (oz) 4.9 5.6 4.1 5.2 4.9 5.6 4.8 4.6