You can't call a phone (or indeed, anything) a "Mini" without it being small, and indeed at 58 by 108 by 18.1 millimetres, the XDA II Mini is a small smart phone, although of course it's still only moderately sized from the phone side of the equation. In visual terms it's not a great departure from the XDA II itself; you've got a directional button at the bottom of the phone, surrounded by four selection buttons (including the two call buttons), and a 2.8-inch display with a total resolution of 240 by 320 pixels. At around 150 grams, it's much lighter than the XDA II or XDA IIs, but you'd expect that from a smaller smart phone.
The XDA II Mini runs Windows Mobile 2003 Second Edition for Pocket PC Phone Edition -- try saying that three times fast -- on an Intel PXA 272 processor running at 416MHz. With 64MB of Flash ROM and an equal quantity of RAM, it's heavy on the storage side for a phone, but if you're looking for serious PDA usage, you may want to avail yourself of the SD/MMC card slot that sits atop the phone.
Running a variant of the Pocket PC OS means it's preinstalled with the most common PDA applications from the Pocket PC side of the fence -- Word, Excel, PowerPoint Viewer and so on -- as well as some custom O2 applications. Like the other XDA units, the Mini sports an integrated digital camera, and in keeping with the best that we're seeing in mobile phone cameras at the time of writing, it's a 1.3 megapixel unit, which should put it just into the acceptable and printable category.
As a phone, the XDA II Mini is tri-band GSM and GPRS capable, and as it's a smart phone with visual keyboard facilities, creating and sending SMS and MMS messages is a snap. It's also Bluetooth capable, although that's not the only way to synchronise it with a suitable PC; a USB cable is also provided.
The first thing we noticed about the XDA II Mini is a common fault with smart phones lacking an integrated keyboard; the screen smudges quickly and often; we'd suggest carrying a cleaning cloth around with you if you're keen to show this phone off to your friends. Aside from that, the display is clear and bright, with the usual adjustments for maximising battery life by dipping screen brightness depending on your situation. As a phone we had few complaints about its performance, aside from one situation where it for some reason it incorrectly grabbed contact details for somebody phoning us -- although to be fair to O2, it does note on the splash screen of our review unit that it's a test unit, so some bugs are probably inevitable.
As a PDA, the XDA II Mini sits well in a competitive category, although there's not too much that really catapults it ahead of the competition per se, and the fact that the rocker on the side of the unit doesn't perform scrolling functions -- it's a volume control for the PDA and phone capabilities -- threw us for a while.
The XDA II Mini's camera is one of the better implementations of a mobile camera we've seen for a while; it's undoubtedly helped by having a rather larger than normal LCD for you to frame shots with, and wisely, there's a focus on fun shots -- including a number of silly shot templates to frame with -- rather than serious photography. Predictably, without a flash, you'll end up with a number of rather dingy looking photos at night, but daytime shots perform well.
O2 claims a battery life of around 180 hours standby and 4-5 hours talk time with the XDA II Mini's 1,200 mAh Lithium Ion battery, although in our testing we'd suggest it's capable of less if you're using the PDA functionality much -- we averaged around 2-3 days before needing to recharge the battery with only moderate usage, and predictably much less if the integrated Bluetooth was switched on.