A list of people who might need a phone that sprawls as far and wide as the Infuse: Godzilla, Shaq, the Nathan's hot dog contest winner who isn't the Japanese guy, people who'd giggle every time they say, "My phone is bigger than yours."
WHY IT MATTERS
The funny thing about choices—at least when it comes to computers, smartphones and politicians—is their tendency to melt together into amorphous, indistinct blobs. In the case of phones, they congeal into hulking black slabs, a lot of them running Android. It's hard to stand out. (How many formerly epic 4.3-inch phones are there now?) Unless you're genuinely outstanding. The Infuse, at 4.5 inches, is the next logical step. The fundamental questions: Does the human race need a phone this big? How long before other phones are just as gigantic? Can a phone possibly get any bigger?
A refrain: Size matters. Samsung has accomplished a genuine feat of engineering here, divining the absolute limits of how large a phone can be before it ruptures the boundaries spacetime and the English language. You'll feel a surge of dork shame shimmy down your spine every time you pull it out in public, or press it against your face (unless you are a huge dork, live in Asgard or have a deep, unironic appreciation for things sized according to the same design principles as clown shoes). But it is usable, for a single reason: It's very, very thin. Meaning even your tiny human hand can wrap around it, if not entirely comfortably. But is 4.5 inches better than 4.3 or 4 or 3.5 inches? No, maybe, yes—in that order.
AT&T calls this a 4G phone, and while they're not quite lying with a shit-eating grin—it's on average around 5x faster on AT&T's network in NY than an iPhone 4 in spots I tested—it's terribly, terribly inconsistent. But hey, the battery life in this thing is all-day, despite powering a screen approximately the same size as the one in the Dallas Cowboys' stadium. The software is basically the same as the current Captivate on AT&T—Android 2.2, with Samsung's glommed on, oh-so-glossy TouchWiz interface.
Super AMOLED Plus is perhaps better than any phone screen technology out there except the retina display, even with its 800x480 pixels stretched across the wider canvass. Colors are super rich, blacks are inky, and it's usable enough in sunlight. It's fairly quick. And this is one of the better phone cameras I've seen in a while, with solid 8MP stills and pretty okay 720p video. (Also Samsung's custom software, which echoes its point-and-shoot cameras is a plus—the sole nice thing I have to say about TouchWiz).
Sorry, but there's not a single carrier or phone maker on the planet who currently makes an interface that's better than Google's for Android. They're all worse, more confusing, uglier. (The ability to install custom UIs after rooting doesn't negate this. Normal people don't root their phones, they just complain about them sucking.) Non-removable bloatware, while minimal here, is increasingly agitating on Android phones. The tradeoff Samsung made to offset the juggernautiness with lightweight plastic makes it feel cheap. More pixels would be more better, since it'd make text sharper in lots o' cases. AT&T's 4G branding, at least in NY and SF.
SHOULD I BUY IT?
Because the Infuse would be borderline generic if it weren't so massive, like a washed-up action movie star, this is one of those easy yes/no questions: Do you want a humongous phone?