1. Samsung Galaxy S II Skyrocket

• Offers a killer 1.2 GHz dual-core Exynos CPU, and is incredibly smooth and lag-free
• Samsung's TouchWiz 4.0 UI is a night-and-day difference from previous builds, and can compete head-to-head with HTC's Sense and Motorola's UI
• Feature set is fantastic, and it's nice to see it available in subsidized form

• AT&T's version has a 1,650 mAh battery, and it struggles to make it through the day with moderate use

2. HTC Vivid

Pros
    •    iPhone 4 builds on a successful formula with a thinner, more luxurious design, higher resolution display, and improved camera paired with a front-facing camera and video-calling software
    •    Improved wireless radio (reception) and better voice quality thanks to dual-mic noise cancellation
    •    Best HD video capture from any mobile phone we've ever tested
    •    Out-of-the-box iTunes compatibility bests offerings by any other mobile platform
    •    Battery life is impressive

Cons
    •    "Death Grip" issue has led to widespread reports of severe signal loss when phone is held a certain way

Summary

Despite its highly publicized antenna problems, iPhone 4 is one of the best smartphones on AT&T. Whatever you think of Apple's approach to smartphones, iPhone 4 is incredibly thin, has the best display ever to grace a mobile phone, and serves up state-of-the-art media capabilities. Some will prefer an Android phone because they prefer Android, and as of right now, the Samsung Galaxy S II offers a better combination of features. For everyone else, though, iPhone remains the smartphone to beat.

3. Apple iPhone 4S

Pros

    •    4-inch qHD display looks nice, and strikes that perfect balance between the "too small" 3.7-inch displays and the "too big" 4.3-inch displays.
    •    First phone to offer NVIDIA's Tegra 2 dual-core processor
    •    With the option of a laptop dock, multimedia dock, and more, Motorola has created a great accessory ecosystem
    •    Android 2.3 and Motorola Applications Platform update make the Atrix 4G a whole new phone

Cons

    •    Somewhat cheap, plasticky feel
    •    Camera is only 5-megapixels, though picture quality appears to be better than Motorola's 8-megapixel devices

Summary

Forget the dual-core 1 GHz dual-core NVIDIA Tegra 2 CPU and 4-inch qHD display.  Thanks to Motorola's old user interface - MOTOBLUR - the Motorola Atrix 4G suffered from a terrible amount of lag when it launched in March.  Thankfully, the recent Android 2.3 update completely rectified the issues that the device was facing.  The lag issues from the past have been completely resolved, and the phone zips through anything thrown at it.  With sideloading enabled, Gingerbread installed, and a much-improved build of Motorola's UI on board, the Atrix 4G is finally ready for primetime.  Combine the updates with a fantastic accessory ecosystem and a powerful spec sheet, and the Atrix 4G moves past the HTC Inspire 4G to become the second place smartphone on AT&T.