The Samsung Galaxy S III is the latest salvo in the war between Android and iOS, and it’s a doozy.

Lighter and thinner than the iPhone 4S, the Galaxy S III also packs a 4.8-inch screen, dual-core processor, impressive camera and a handful of extra distinguishing features such as S-Voice, a Siri competitor.

Performance-wise, I had very few issues. The U.S. version of the phone has a dual-core processor instead of the quad-core chip in the international version, but I saw very few stutters or problems even when putting the phone through its paces. The phone is running a Samsung version of Ice Cream Sandwich, meaning the software is solid though there are a few apps that don’t work with this latest Android version. That, at least, will change over time.

Heat was not a problem with this phone; it stayed relatively cool throughout all my testing. The battery life was a little shorter than I would have liked, especially considering that the screen is supposed to dim when it senses you’re not looking at it. The phone made it through a full day, but just barely — it’s probably a good idea to keep a charger handy at your desk.

There are interesting optional motion gestures on this phone, though some border on gimmicky. You can swipe the edge of your hand over the screen to take a screenshot, or shake your phone to scan for other devices. One I found genuinely useful was the option to mute your phone by placing it face-down.

S-Voice has the same problems that I’ve had with Apple’s Siri; it doesn’t always understand me. So while it can launch apps and work with other part of the phone’s system, it didn’t end up being any more useful. It didn’t quite have the hang of natural language, and I ended up repeating myself, just as I do with Siri.

There are a lot of sharing features on the phone as well, though some — such as a feature that lets you share photos in real time — only work with other Galaxy S III’s, limiting their usefulness. Speaking of photos, Samsung’s camera app outdoes itself with add-ons such as a feature that takes several pictures and then chooses the best one. The sensor on the device is fantastic, though the phone itself lacks a dedicated camera button.

In terms of design, Samsung’s done a good job of making the phone distinctive, shipping white and “pebble blue” versions. The phone is so thin that even with that huge screen, it didn’t feel at all bulky, though slipping it into some pockets was a challenge. The plastic casing didn’t feel too cheap. And while the blue handset I had on loan from T-Mobile was prone to smudging, it didn’t suffer any more permanent damage when thrown in with my keys and other briefcase junk.

My only complaint with the design is that the home button, which is small and low on the phone, was kind of hard to get to with one hand, and tended to make the phone tip when I tried.

What has always set Samsung phones apart, in my view, is the screen. That’s true, too, of the Galaxy S III, and not just because of its size. The color on the display is slightly cooler and darker than other phones, but the picture is great once your eyes adjust. You can see some pixels on the display, which may turn off retina-display devotees, but the big screen makes reading and browsing a breeze.

So is it an iPhone killer? Let’s call it a worthy contender.

It’s not worth breaking your current contract over, but if you’re in the market for a new, top-of-the-line Android phone — around $200 on a two-year contract — then this is should be a top consideration. And with the Samsung Galaxy S III launching on all four major U.S. carriers, it certainly won’t be hard to find.

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