Reviewing the iPhone 4S is in many ways a lot like reviewing the original iPhone 4, except that it's not. The device, which was just announced at a special event on Apple's campus, is very much the same phone the company released in June of 2010 — but it's also something completely new.

While much of that sameness comes from an identical physical appearance, and nearly identical specs (in some places), there's much that's fresh here. Besides packing the successor to Apple's custom A4 CPU (appropriately dubbed the A5) inside, the iPhone 4S also sports an upgraded rear camera, an improved antenna design, and a new internal radio that allows the device to perform double duty on both CDMA and GSM networks.

In reality, however, the hardware is only half the story. Maybe not even half. The introduction of the iPhone 4S marks the introduction of iOS 5 as well. The new operating system is loaded with big improvements, from notifications to how your device connects to your computer. Packed with major features like iCloud integration and an innovative, voice-activated "intelligent assistant" named Siri, it's not unfair to consider this one of the most meaningful updates to iOS we've ever seen.

For a phone that's already being touted as one of Apple's fastest-sellers, it's hard to even suggest that the iPhone 4S won't be a success. But beyond pure market excitement, is there enough in this new device to stand up to a steady wave of competition — some which is awfully fierce? I'll try to answer that question in my review below, so read on for the whole story.