Apple's iPhone 4S has some unique features that make it tough for Android phones to knock off. Siri, the digital voice assistant is one feature none of the Android sets in this list have.

Apple also has its own operating system that, if it lives up to its promise, will also be a contender until iPhone 5 gets here. Besides that, iPhone 4S doesn't have the variety and flexibility to be found in Android phones, so its only a matter of time before public opinion shifts away from Apple as the number one smartphone maker.

Samsung's Galaxy S2 leads off the list of top five iPhone rivals, but there is another Samsung phone on this short list and it promises, Something Big is Coming. Here are the top five iPhone 4S rivals.

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