is here. Cupertino's mobile operating system brings advanced, centralized notifications, cable-free setup, wireless iTunes syncing, and other enticing features to the iPhone, iPad, and iPod touch. It's certainly attractive software, but it isn't the only new smartphone OS packing a wealth of goodies; , , and are also very competent competitors.

Using the recent Apple iOS 5 release as the baseline, we've highlighted several of the operating system's most exciting features and compared them to its rivals. Below we've charted the results as simply as possible, but be advised there are nuances to particular comparisons. For example, in all cases there are plenty of third-party apps that may fill in gaps found in the base operating systems. Furthermore, when it comes to Android, OEMs tend to skin the phones (albeit with mixed results), often adding additional functionality to the stock version of Android. In order for any sort of comparison to work, we're looking at what potential smartphone purchasers get out of the box on stock versions of each mobile OS. Yes, all of these OSes can be expanded with downloadable apps; no, that's not the point of this story. Check out the table first, and then take a look at our explanations of each category and the caveats that go with it.

Please note: Apple iOS 5 is only compatible with certain iOS devices. These are iPhone 3GS, iPhone 4, iPhone 4S, iPad, iPad 2, and iPod touch (third and fourth generations). iPhone, iPhone 3G, and iPod touch (first and second generations) are not compatible.





Unified Notifications

When it comes to unified notification systems, Apple's newly-minted Notification Center bears quite a resemblance to that of Android. As with Android, iOS 5 lets you access notifications from the lock screen or, when using the phone, pull down a tray of notifications from the top of the screen. Blackberry 7 OS pins updates to the home screen. Windows 7.5 Mango uses live tiles, which is a bit less unified, but works within the context of the operating system.

Location-Based Reminders

All four mobile platforms allow users to set basic reminders, but no one can touch iOS 5's Reminders tool on account of its geo-fencing location-based notifications. With Reminders, iOS users can set alerts that activate when they enter or exit specified locations.



Quick-Camera Access

If you're using your mobile phone as your cameraas more and more people are beginning to do, for better or worsequick access counts. Both Windows 7.5 Mango and iOS 5 let users jump directly into camera mode from the lock screen without entering passcodes (if enabled). Blackberry 7 OS allows users to map a side button to launch a camera, but unfortunately you'll still need to unlock your device. Certain Android phones (such as the HTC Sensation) have quick-camera access, but stock Android handsets do not.



Advanced Photo Editing Tools

When it comes to photo editing on the go, iOS 5 is a clear winner out of the box. While Android allows some editing (crop and rotate), iOS goes a step further (crop, edit, red eye reduction, composition controls, and auto-enhance). BlackBerry 7 OS and Windows 7.5 Mango can't compete here.

PC-Free Setup

Desktop-free setup and updates is one area where Apple played serious catch up with iOS 5. It now joins all the other platforms in the (sort of) post-PC world as you no longer need a Mac or PC to activate an iPadit's used out of the box as a standalone device.



Wireless Sync

Apple has delivered a powerful wireless sync solution: Everything in your iTunes libraryincluding photos and videocan sync over the air if your iPad and computer are connected to the same Wi-Fi signal. In this respect, iTunes Wi-Fi Sync tops Blackberry 7 OS, which handles music, but not video. One caveat: In order to activate , you must first connect the iPad to a Mac or PC to activate this feature. Mango phone owners can now sync Office 365 and SkyDrive documents. Gingerbread lags behind the competition in this category.

Voice Commands

Voice Control isn't new to smartphones, but Apple's Siri implementation takes the feature to a new level. You can use the "intelligent personal assistant" to look up information, calculate tips, launch a handful of compatible apps, and other useful activities simple by speaking a question or command; it will even ask you follow up questions in order to correctly cull information. It's not perfectit sometimes doesn't recognize words or phrasesbut it's pushing voice control in a way that its competitors can't match.

The Best Smartphone OS?

Let's be frank: This article is measures everyone else by iOS 5's standardsafter all, we're comparing its features (many of them unique) to what other operating systems have to offer. That doesn't mean that iOS is the right mobile OS for everyone. Android 2.3 Gingerbread is tweaker-friendly; BlackBerry 7 OS has a strong enterprise focus with its data security and built-in Microsoft Office editors; and Windows Phone 7.5 Mango is great for social networkers with its smart, intuitive Groups feature. Still, Apple iOS 5 does push the envelope, features-wise, and is one that continues to innovate in the mobile operating system space. But the release of Android Ice Cream Sandwich could be only days away; once we've had a good look at it, we'll update this article from the point of view of Google's smartphone OS, and that might be a different story.