The iPhone 6s ($649; 16GB) is faster than last year's model, but that isn't the only change Apple's latest smartphone brings to the table. If you're an existing iPhone owner, the upgraded cameras on the 6s will immediately impress you, and the support for AT&T's new Band 30 network will help reduce congestion and stalls as it rolls out nationwide. It's a worthy upgrade, and our Editors' Choice for smartphones on AT&T.

Our main iPhone 6s review covers the T-Mobile unit. Here, I'll talk about AT&T-specific testing and features. 

Unlike the iPhone 6s for Sprint, T-Mobile, and Verizon, there's a slight physical difference with the AT&T unit. The AT&T model has the new frequency band, which means if you're an AT&T subscriber, you want to get the AT&T-specific model for the best network performance.

The difference between the iPhone 6s and last year's iPhone 6 on AT&T's network isn't just Band 30, which hasn't yet rolled out across most of the country. The new model's Qualcomm X7 modem also recovers from dead zones faster than the iPhone 6's X5 modem, improving network performance across the board.

 See How We Test Cell Phones

The 6s supports AT&T's voice-over-LTE (VoLTE) system, including high-quality voice calls to other AT&T phones. It also supports Wi-Fi calling, now that AT&T has resolved its issues with the FCC. You can toggle both features on an off as you please.

AT&T service didn't change battery life in my testing, which has been consistent across all carriers. Our iPhone 6s showed slightly shorter battery life (4 hours and 21 minutes of full-screen video streaming over LTE) than the iPhone 6, which got 4 hours and 33 minutes on the same test.

From left: Galaxy S6, iPhone 6s, iPhone 6, iPhone 5.

Comparisons and Conclusions

AT&T subscribers have a lot of choices. Along with the iPhone 6s and the iPhone 6s Plus, AT&T supports all the flagship Android phones, and it'll be the only carrier to bring Microsoft's Lumia 950 to market. So why choose Apple, and why choose the smaller iPhone 6s over the 6s Plus or last year's 6?

I believe that network performance is at the core of the mobile experience, and the better modem is the most important reason to buy this year's iPhone as opposed to an iPhone 6 or an iPhone 5s. The effect AT&T's Band 30 has will be less immediately dramatic than T-Mobile's Band 12, for example, but as the years go on, you'll find yourself better able to zip along the Internet where people with older devices choke.

As for the 6s versus the 6s Plus, that's almost entirely about size in the hand. The 6s Plus takes better, smoother videos. But I don't think that should be your deciding factor. For many people, the 6s is much more convenient device to use because it fits in one hand.

There aren't many high-end Android phones that are in the 6s size range—most of them are sized more closely to the 6s Plus. The leaders in terms of one-handed Android phones are the Samsung Galaxy S6 and the HTC One M9. Performance on the Galaxy S6 is very similar to the iPhone 6s, although the Galaxy doesn't have Apple's new 3D Touch pressure-sensitive screen. The HTC One M9 is a bit bigger, but still a basically one-handed device.

Ultimately, you're choosing based on the ecosystem. Apple gets the latest and best third-party apps, especially games and social networks, first, and its comprehensive network of retail stores means you don't have to go to your carrier for help. Android is still more configurable, although Apple has closed some of that gap with iOS 9. We think iOS's smooth, simple operation and excellent app library make it more appealing to a huge number of people, so the iPhone 6s gets our Editors' Choice for smartphones on AT&T.