Review: Nokia Lumia 900 for AT&T
Screen
The 900's display is typical for a Windows Phone. It measures 4.3 inches and includes 800 x 480 pixels. It's no Retina Display in terms of pixel density, but it's still good for most users. Nokia employs something called ClearBlack to make the OLED panel stand out. It's inky black, but bright and colorful when it needs to be. It's kind of crazy how readable the display is outside under bright sunshine. I was able to read emails — small text on a white background — with no problem under direct sunlight.
Signal
The 900 works with AT&T's nascent LTE 4G network and its much-more-widely-available HSPA+ network. The 900 performed in-step with other AT&T devices. For example, when under HSPA+ coverage, it exactly matched the signal strength of other AT&T phones. I didn't have any trouble making calls, nor receiving them, no matter what the signal indicator read. HSPA+ delivered good internet speeds during my time with the 900, and it didn't matter if the network coverage was weak or strong, the 900 was consistently good. With respect to LTE, in the time I spent testing the 900 in NYC, it was very fast. The connection waffled between HSPA+ and LTE a bit, but when it showed LTE it was lightning-bolt quick.
Sound
True to Nokia's legacy, the 900 is an excellent voice phone. The earpiece is plenty loud for most any environment, and the calls I made were clear of noise and interference. The speakerphone was also nice and loud, though voices were slightly more prone to a bit of distortion when routed to the speakerphone. The ringtones can be set loud enough that others might mistake them for emergency vehicles. In fact, I'd avoid setting them too high, as you're likely to wind up with an earache or headache. Don't turn them off entirely, though, as the vibrate alert is too weak.
Battery
The 900's internal battery is good for a bit more than a full day's use. With two email accounts, plus Twitter and Facebook tugging at AT&T's network throughout the day, the 900 still had plenty of power left at dinnertime. I was able to download a dozen applications whilst watching TV and stay on top of my RSS feed all evening without denting the battery life. This was under HSPA+ coverage only. In the short time that I tested the 900 under LTE coverage, I did notice the battery drained at a faster rate.