Facebook’s big step into mobile is finally live for a select set of Android phones from Samsung and HTC. Facebook Home, the suite of apps that puts the social network at the heart of the smartphone, is available for download from Google’s Play store.

The Facebook Home update itself, essentially the part of the software that puts Facebook updates on users’ screens and launches apps, can be downloaded for the Samsung Galaxy S III and Galaxy Note II and HTC’s First, One X and One X+ phones. It will also be available for the upcoming Samsung Galaxy S 4 and the HTC One.

Users should also update their Facebook Messenger and Facebook network apps for the “full Home experience,” according to the description on the company’s app download page.

Facebook Home is tailored to please the most avid Facebook users, making friends’ updates the central focus of the smartphone. The phones’ lock screens display a running feed of updates, and users can comment or “like” posts straight from that screen. Photos are full-screen and zoomed-in fit the particular device. That means that some photos don’t look all that great because of low resolution. Users can zoom out of photos by holding a finger down on a particular picture. A double-tap will register a “like” on the photo or update.

First, the pros:

The HTC First, which comes pre-loaded with Facebook Home, will be available in stores on April 12. Pre-orders for the phone start April 5; the phone costs $99.99 on a two-year contract. (Courtesy of AT&T/Courtesy of AT&T)

● The interface is made for true Facebook fans who don’t like to have to pop into the separate app every time they want to check a message, post an update or check in.

● The update to Messenger, which users can get without completely upgrading to Home, is pretty nifty, as it will display conversations over any open app. Users can respond in-line to messages without leaving an app and move notifications around the screen to their preferred spot. Users can also write comments on posts or like posts without unlocking the phone.

While Facebook Home certainly makes using the social network much more convenient on mobile, there’s also a lot that could give users pause — particularly on privacy.

● Certain activities, such as launching apps, posting updates to your own feed and checking messages, stay behind the lock screen. But the default setting puts the photos and text posted by friends on display for anyone who can see the phone screen.

● Users can put Home behind their lock screen, but they have to go into their settings to do so. The settings menu also lets users manage settings for Messenger and links to general settings for Facebook.

● In terms of usability, the Facebook skin can make it feel like you’re flipping between two different systems. Users can set favorite apps to launch from the Facebook Home home screen, but they have to swipe to a different screen to reach all of their apps. While that’s much of a problem, it does require smartphone users to overwrite their habits — which people are often loathe to do.

● Finally, Facebook Home takes away some of what draws people to the Android platform in the first place — the ability to truly customize the home screen. Installing Facebook Home means saying goodbye to any widgets that may have been parked on that screen and instead accept the grid layout that Facebook presents for apps.

All in all, Facebook Home is ideal for true social network addicts. But those who aren’t constantly checking Facebook mobile for updates might find it more distracting than helpful.

(Washington Post Co. chairman and chief executive Donald E. Graham is a member of Facebook’s board of directors.)

Related stories:

Among Internet critics, Facebook Home may prove as divisive as Facebook itself

Will Facebook Home really change the way we use our phones?

Microsoft to Facebook: We had the idea for ‘Home’ two years ago

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