Apple's latest iPhone, iPhone 4S, which was unveiled on Oct. 4 along with iOS 5, iCloud and Siri Voice Assistant and is set to hit the shelves of AT&T, Verizon and Sprint on Friday, Oct. 14, has smashed previous pre-order records by registering 1 million preorders on the very first day.

iPhone 4S features A5 dual-core processor, 8 MP all new camera, voice assistant Siri, and a larger storage capability (up to 64GB). One of iPhone 4S' most important features is iOS 5 delivered on Oct. 12, which has over 200 new features, including Notification Center, iMessage, reminders, Safari and Twitter.

But when you hold an iPhone 4S in your hand, you might think it is an iPhone 4, because the major designs were not changed. Both of them have 3.5-inches Retina display, two versions (white and black), glass backs, and both rear- and front-facing cameras.

There are no major differences except some hardware upgrades between iPhone 4 and iPhone 4S. The new iPhone will hit stores on Friday, Oct. 14. Will you buy an iPhone 4S rather than an iPhone 4? Here are top 10 reasons why you should buy an iPhone 4 and save some money.

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iOS 5
iOS 5 REUTERS
iPhone 4S camera
iPhone 4S camera REUTERS
iCloud is also available on iPhone 4
iCloud is also available on iPhone 4 REUTERS
Apple CEO Tim Cook speaks in front of an image of an iPhone 4S at Apple headquarters in Cupertino
Apple CEO Tim Cook speaks in front of an image of an iPhone 4S at Apple headquarters in Cupertino REUTERS
NFC
NFC REUTERS
4G
4G REUTERS
Siri
Philip Schiller, Apple's senior vice president of Worldwide Product Marketing, speaks about the iPhone 4S at Apple headquarter. REUTERS
moble Carriers
iPhone 3GS is available only to AT&T customers, while both iPhone 4S and iPhone 4 are available to AT&T, Verizon and Sprint customers. You can choose any of them by yourself. REUTERS
Apple CEO Tim Cook
Apple CEO Tim Cook REUTERS
Iphone Twitter Iphone Iphone