The minute we took the I-mate JAMin out of the box, we thought we were seeing double. Small, black and with rounded edges, the JAMin bears a striking resemblance to the new O2 XDA Atom.

As well as its diminutive form factor, the JAMin shares much in common with the Atom, though there are a few key differences. While both the Atom and JAMin units are coloured black, the Atom has a glossy finish that we found very prone to picking up fingerprints. The JAMin on the other hand, doesn't have this glossy overlay so this problem didn't occur at all.

Tipping the scales at only 150g, the I-mate JAMin is a far cry from some of the behemoth smartphone models we have seen in the past. With its organiser functions and attractive styling, this phone can be used for both business and pleasure alike.

The screen resolution of the quadband JAMin is 240 x 320 pixels, the same as on the triband Atom. The JAMin screen however, only supports 64K colours, while the Atom extends this to 262K. We had no real issues using this screen but did find it very difficult to keep clear of smudges and fingerprints. After using this product for nearly two weeks, we'd also recommend using a case or screen protector in case the screen gets scratched or damaged.

The call buttons, 5-way joystick and shortcut keys are all placed under the screen. A USB 1.1 connection is at the base of the unit, along with a 2.5mm headphone jack (meaning you can't use an ordinary pair of headphones). A camera shortcut, volume slider and connection shortcut are on the left while an SD slot is placed on top. We are pleased to see the more commonly used SD format supported (rather than the mini-SD on the Atom), for the simple reason that we can reuse our existing SD cards rather than purchasing new ones.

While the JAMin runs Windows Mobile 5, we found the performance somewhat lethargic. At first, we thought the Atom's 416Mhz processor would easily outgun the 200Mhz TI processor on the JAMin. But this didn't really turn out to be the case - the Atom is definitely faster, but the difference isn't as great as we thought it would be. Still, we are less than impressed with the processing performance on the JAMin and this alone would stop us from buying one. I-mate claims the benefit of using the TI processor is that it offers battery life improvements, and this was borne out in our testing.

With moderate usage, and Bluetooth and Wi-Fi on, we were able to get nearly 1.5 days of use from the JAMin without needing to charge this unit, which was better than the Atom. The price you'll pay for the moderate increase in battery life however, is sluggish processing performance. There is a noticeable delay when opening applications or performing operations, and while for the most part this is tolerable, it can get frustrating.

The lacklustre processing performance is nowhere more apparent than when opening up the camera application or playing video content on the included Windows Media Player. We found the camera application taking a significant amount of time to open, and we detected a slight lag in some of our test videos. The biggest issue with video content was in fact sound. The speaker on the JAMin is for some unknown reason placed on the rear of the unit, meaning sound is being projected away from you. In fairness to I-Mate though, this is not a phone you would purchase for its multimedia capabilities - the JAMin doesn't even include an FM radio, although one is shipped with the Atom.

Apart from the processor, our main gripe with the JAMin was call quality - the sound of calls was muffled, obscure and impossible to hear in high noise conditions, such as on busy roads. The speakerphone wasn't much help easier, as the speaker is on the back of the unit, making it difficult to hear.

Like the Atom, the JAMin is well equipped in terms of connectivity, supporting Bluetooth, Infrared and Wi-Fi. Unlike the Atom however, which only supports 802.11b, the JAMin also supports the faster 802.11g standard.