(CNN) -- A dizzying number of smartphones is now available in the United States. Picking one is a big commitment, especially when you're signing up for a two-year wireless contract.

There are multiple factors to consider when picking a new phone, such as the carrier, your budget, hardware and the operating system.

Apple, Google and Microsoft each has its own mobile operating systems and ecosystems -- iOS, Android and Windows Phone, respectively -- and they've all been updated in the last year. The three rivals will be going head to head on shiny new handsets this holiday season.

We spent a week or so playing with new phones running these systems to see how they stack up. (For now, we're skipping other struggling smartphone platforms, BlackBerry and Symbian, even though they are more popular globally than Windows Phone. Both are quickly losing market share, although BlackBerry could bounce back when it releases its new smartphone OS, Blackberry 10, in 2013.)

Here are our impressions:

ANDROID

The Android operating system was released by Google in 2008 and has become the No. 1 smartphone OS in the world. It was running on three out of every four smartphone handsets sold in the third quarter of 2012, according to IDC. (The following descriptions are based on the latest version, Android 4.2, aka Jelly Bean.)

Interface

Android has the most detailed interface of the available operating systems, with many options and a lot of flexibility for setting it up to meet your needs. The home screen has a Google search bar at the top, and a bar at the bottom can hold four app icons or folders. The middle button brings up the complete list of apps installed on the phone.

You can place icons for your favorite apps anywhere on one of the multiple home screens, then tap an icon to launch that app. You also can decorate the pages with widgets. Widgets are like interactive mini-apps, and they show live information such as the latest from your Twitter feed, titles in your media library or little photo albums that you can flip through from the home screen. You can add widgets on the lock screen as well.

Dragging a finger down from the top of the screen shows notifications. If you're ever lost, you can just hit the back or home button at the bottom of the screen.

Apps and content

On Android phones, apps, games and content such as movies and music are sold in one unified marketplace, the Google Play store. There are about 675,000 apps and games in this store, which is just below the the number in Apple's App Store.

The devices often come preloaded with extra, unnecessary apps from the phone maker and wireless carrier, many of which try to get you to sign up for some paid service. The same is true for Windows Phone handsets.

A sizable library of movies, music, TV shows books and magazines is also available in the Google Play store.

Key features

Customization and control are big draws for Android users, and the platform is crammed with options.

The latest update adds a fun, swipe keyboard feature called Gesture Typing that lets you spell words by dragging your finger around instead of tapping on each letter.

Google Now uses your location and timing to show you the most relevant information, such as your upcoming flight times and public transit updates. There is voice search, so you can speak questions and search terms into the phone.

And of course, Android has the Google Maps app.

Hardware

Android is available on the largest number of smartphones. There is a device for every price point, and they have different features, manufacturers and carriers.

Because Android is open source, different companies can take the OS and modify it to work with their hardware. That means there are several versions of the same operating system. One of the downsides to this fragmentation is that software updates have to be adapted for each version, and the updates can be maddeningly slow to come to Android devices.

Currently, the only phone running Android 4.2 is Google's own Nexus 4, by LG.

Who it's for

Android is made for anyone heavily invested in the Google ecosystem (Gmail, Google Drive, Google Calendar); people who prefer their maps with public transit directions and a high level of accuracy; people who like control over their computer systems and who are fans of customization and tinkering; anyone looking for a low-cost smartphone and are unable (or unwilling) to pay the Apple premium; and buyers who want a large screen.

iOS 6

Apple's iOS operating system powers iPhones, iPads and the iPod touch. It's is the second top-selling smartphone operating system; 14% of all smartphones sold worldwide in the last quarter were running iOS. The gap between Android and iOS is huge, but keep in mind that Apple's platform only runs on one smartphone line, the iPhone.

Interface

This is the most straightforward interface in the bunch, and it's been relatively unchanged since the first iPhone came out in 2007. There have been nice minor tweaks, such as the addition of folders and notifications, but the gist is the same.

The home screen displays icons for each app; they aren't stashed away in any second location. You can organize apps in folders or search for them using the Spotlight search feature.

The iPhone doesn't display live-updating content on the home screens like Android and Windows Phone devices do. It does have a notification center and notification badges that can appear on icons. The lock screen isn't very customizable beyond the background photo.

A fixed dock along the bottom of the screen can display the four apps you use the most.

Apps and content

Apps must be purchased in the official Apple App Store, which currently has more than 700,000 apps and games in stock. The importance of a platform with a large volume of apps is overblown. What matters is the availability of quality apps and the willingness of major developers and companies to produce good products for that platform.

Content including music, movies, TV shows, podcasts, books and audiobooks are purchased through the well-stocked iTunes Store, though you can also buy them through another company such as Amazon and synch them to your iPhone. Books are also available directly through the iBooks app.

Apple has the tightest control over its operating system and the heaviest hand when it comes to editing exactly what features reach the final product. That means no extra preinstalled apps, just the necessities.

Key features

The iPhone is iOS's killer feature. It is a stunning piece of industrial design, and the newest version is durable and lightweight.

The voice-assistant feature, Siri; ease of use; and high-quality, third-party apps are other big selling points. If you're near an Apple store, the free tech support is a great perk.

Hardware

Apple's iOS operating system only runs on Apple's iPhone, iPod touch and iPad. The latest version, iOS 6, runs on the iPhone 3GS, iPhone 4, iPhone 4S and the iPhone 5, though some features such as the camera's panorama mode and Siri are only available on the iPhone 4S and later.

The cheapest phone currently sold by Apple is the iPhone 4, which costs $450 unlocked but is free with a two-year wireless contract when you buy it through AT&T, Sprint or Verizon.

Who it's for

iOS is designed for people who want a simple interface; nontechnical types who will appreciate the convenient and free hand-holding available at the Genius Bar; Mac users; and design lovers.

WINDOWS PHONE 8

This is the second generation of Microsoft's Windows Phone operating system, which began in 2010. Windows Phone 8 was launched in October, and Microsoft hopes the expensive marketing campaign and improved features will help it climb up from fifth place. Last quarter, only 2% of phones sold in the world were Windows Phone devices.

Interface

Instead of icons, the Windows Phone 8 home screen is covered with a quilt of brightly colored squares and rectangles. Each tile can display live information, such as a photo album or your newest e-mail, which can save you a trip into the sometimes jumbled innards of the operating system.

A swipe to the left brings up an alphabetical list of installed apps. Tap and hold on an app to place it, or "pin" it, on the start screen. Tap a tile and hold to change its size or placement.

There are some odd design choices, such as allowing text to be cut off randomly to make the most of the smartphone screen. Overall, the design relies on flat, simple images and a lot of large text. By default, the text is mostly white on black, which is jarring but saves battery life. You can switch it to black on white and change the color of your tiles.

It's possible to display personalized information on the lock screen, such as your most recent calendar event, e-mail, text message or missed phone call.

Apps and content

The current app selection on Windows Phone 8 is the smallest of the three platforms, but Microsoft is working hard to woo developers. The system shares its underlying framework with Windows 8, so that may make it easier for developers to make apps for both platforms.

Like Android phones, there is usually some preinstalled clutter -- apps from carriers and manufacturers -- on Windows Phones, but these can be deleted easily.

Tunes are available in the Xbox music store, but you have to sync movies and TV shows over from a desktop application. Pandora radio comes preinstalled along with a free year of ad-free service. Nokia phones have the Nokia Music service installed.

Key features

The main screen is the winning ingredient for Windows Phone 8. It's simple, fun and easy to understand, and it does a great job of surfacing important information.

Kids Corner is nice touch for parents. It creates a separate profile for kids, limiting them to approved apps and keeping them out of your personal accounts. Data Sense is a new feature Microsoft claims will help optimize the amount of data you use.

As part of its latest marketing push, Microsoft has been talking up the "people" angle of the phone for consumers (for example, the Rooms feature is a nice way to communicate with custom groups of people, such as family members). However, the company might be better off promoting Windows Phone's business side. Working with Office documents and syncing them across devices is much easier, and there are built-in features for large companies that need to support phones for employees.

Hardware

The new version of Windows Phone adds support for more advanced hardware than its predecessor, including phones with higher resolution screens, multicore processors and near field communication. So far, there are only a handful of Windows 8 phones available, from HTC, Samsung and Nokia. The most anticipated of the bunch is the Nokia 920, which features a powerful camera.

Unfortunately, people who already own a device running Windows Phone 7 will not be able to upgrade to the new operating system. To upgrade the OS, they must purchase a new phone.

Who it's for

Windows is the most used operating system in the world, and Microsoft CEO Steve Ballmer has said he thinks 500 million people will be using Windows 8, the newest PC/tablet operating system, by the end of 2013. Windows Phone 8 will be best as a companion device for people using Windows 8 on a PC. It's also a nice choice for people who want a simple and customizable interface; heavy Microsoft Office users; parents; and anyone who likes to root for (the corporate overlord version of) the underdog.