The new flagship smartphone from the world's number-one mobile phone company, Samsung's Galaxy S III ($199.99 with contract) is literally a huge achievement. If you love big phones with lots of options, the GS3 will deliver state-of-the-art performance with bonus sharing and media features that you're likely to continue discovering a year from now. For its overall performance and quality, the Galaxy S III  is our new Editors' Choice for touch-screen smartphones on AT&T.

Editors' Note: The Samsung Galaxy S III models on all four major carriers are extremely similar, so we're sharing a lot of material between our various reviews. That said, we're testing each device separately, so read the review for your carrier of choice.

Physical Design
All of the new Galaxy S III models look the same, except for the carrier logo on the back panel. Each is available in dark blue or white (AT&T also has a red option coming this summer), and they're some of the biggest phones we've ever handled. At 5.4 by 2.8 by 0.34 inches (HWD) and 4.7 ounces, the GS3 is slightly bigger than the already-large HTC One X ($199, 4.5 stars), although it's still noticeably smaller and lighter than the Samsung Galaxy Note phone/tablet hybrid ($299, 3 stars).  That said, this is not a phone for folks with small hands.

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I'm not a fan of the huge phone. But I've given up on panning them because every time I suggest these handsets are too big, I get pummeled by comments from people who adore them. Huge phones are the thing. I accept it.

The all-plastic body feels a little less high-end than the exotic materials of the HTC One series, but the phone is solidly built, and light despite its size. The front of the phone is dominated by the 4.8-inch, 1280-by-720-pixel Super AMOLED HD screen. Yes, it's PenTile, which can sometimes look slightly pixelated. But, no, you probably won't notice. Below the screen, there's a physical Home button, as well as light-up Back and Multitasking buttons that start out invisible, so you have to memorize where they are or change a setting to keep them illuminated. The 8-megapixel camera is on the back panel, which, thanks to its reflective finish (on the blue model), doubles as a pocket mirror. 

The default Automatic Brightness setting makes the screen too dim. Kill it and pump up the brightness and it's fine, even outdoors. It's not as bright as the One X's Super LCD 2 display, but it's fine.

Unlike the competing HTC One X , the S III has a removable 2100mAh battery. Taking off the back cover also reveals the microSD card slot, which supports cards up to 64GB.

Call Quality and Internet
If you're interested in call quality, buy the Galaxy S III. Don't buy any other phone. You get advanced call quality features I've never seen anywhere else, and they make a real difference. What's best: Unlike HD Voice in the Sprint HTC EVO 4G LTE ($199.99, 4 stars), they don't require network support. Default call quality is good. Volume is on the high end of average, with no distortion from loud inputs. The speakerphone is loud enough to use outdoors. The microphone does a good job of cancelling background noise. Bluetooth headsets work fine with Samsung's "S Voice" voice dialing system.

But as with so many things here, call quality gets richer if you burrow down into the GS3's settings screens. A volume boost button throws the phone into a super-loud, quasi-speakerphone mode for noisy areas, but that's just the start. There's also an option to set custom call EQ: The phone plays you a sequence of quiet high and low tones and you tell it which ones you can hear, and then it EQ's calls accordingly. This is pretty radical stuff. I prefer my calls sharp, with more high-end, for instance, and the GS3 offers that. This all makes the GS3 the best voice phone on AT&T.

For data, the GS3 hits AT&T's super-fast LTE network, along with global HSPA+ and Wi-Fi on both the 2.4GHz and 5GHz bands. Bluetooth 4.0 and NFC are also on board. AT&T still blocks Google Wallet, but Samsung found its own uses for NFC, which I'll get to below.

Our battery test didn't complete because we ran out of time. But that's good; we still had about 20 percent battery left after a 9 hour, 17 minute call. This phone lasts, and considering the battery is removable, you can carry a spare. That's something you can't do with the HTC One X.

Software and Performance
The Galaxy S III runs Android 4.0 "Ice Cream Sandwich" with a whole lot of exclusive Samsung extensions. Performance was excellent in my tests. The Qualcomm S4 chip running at 1.5GHz is the fastest one we've seen in smartphones so far, and it's able to take on any app challenge you throw at it, including games on the HD screen. Our benchmark tests proved this, although they were within the margin of error when compared with the One X. Both phones are very fast.

Exclusive new features include S-Beam, the ability to transfer files by tapping two phones together and using a combination of NFC and Wi-Fi Direct; S-Voice, Samsung's answer to Apple's Siri; TecTiles, NFC-enabled accessory tags that can change the settings on your phone, and lots of sharing and tagging options in the camera, such as the ability to automatically tag your friends' faces, and the ability for multiple GS3s within a few feet of each other to automatically share all of their photos.

Many of these features work well, but they're almost all buried. The interface is something of a scavenger hunt. Take Smart Stay, a neat new feature which detects your face and keeps the screen from going black while you're looking at it. I love it! But it's not on by default, and the only way to turn it on is by going to the Display area under Settings. S-Beam is similarly buried, under the Wireless menu.