O2's Xda heritage is as old as Windows Mobile itself: O2 was an original hardware partner for Microsoft at the launch of Windows Mobile, and in the UK the network operator has always maintained a strong line of devices.
However the Xda Zest is a first. It's the first Xda to be available on O2's Pay & Go tariff as well as on Pay Monthly. It will be free on some Pay Monthly tariffs, and will set you back £249.99 on Pay & Go.
The Xda Zest has a mid-range price, but the device doesn't compromise on features. With HSDPA, GPS, Wi-Fi and Bluetooth all on-board, most of the bases for a good Windows Mobile handheld are covered.
There is a 2.8in. VGA (640 by 480) touch-screen and even a bespoke interface sitting on top of Windows Mobile 6.1 Professional. This interface offers three screens, accessed by horizontal sweeps of the finger.
One screen displays photo contacts, a second shows applications and settings, while the third (shown above) is a main screen displaying the date and time, weather and messaging updates.
The Xda Zest is quite a squat device, measuring 60.5mm wide by 102mm tall by 16.5mm thick and weighing 120g. The plastic materials used for the fascia are a voguish black and silver colour, and feel robust enough in the hand.
A hold button on the right side of the casing locks out the screen and all buttons, allowing you to carry the device in a pocket without fear of accidental activation.
The headphone connector is mini-USB, making it difficult for you to use a preferred headset. This could prove to be a deal-breaker for some potential buyers.
There is 128MB of RAM and 256MB of ROM, and you can expand storage capacity with microSD cards. The slot is fairly inaccessible as it's located under the battery, which means you need to power down the device to swap memory cards. At the back is a 3-megapixel autofocus camera.
The Xda Zest will come with a three-month trial of the CoPilot Live navigation software.