The HTC Touch Diamond is a slick looking Windows Mobile smart phone that sports a plethora of features in a small and attractive form factor. From the high-resolution display to the built-in GPS receiver and capable 3.2-megapixel camera to the 4GB of storage, everything about this handset screams high end. The Touch Diamond is available exclusively from Sprint for $249.99 with a two-year contract and after a mail-in rebate. It's also available for GSM networks as an unlocked device.

Like its predecessor, the Touch Diamond is meant to be interacted with primarily via the 2.8-inch VGA display, lacking the QWERTY keyboard that you find on many other Windows Mobile handsets. To aid this, HTC has included the latest version of their TouchFlo interface, which is meant to improve the finger browsing experience of Windows Mobile. Unfortunately we found that in practice the TouchFlo interface can be slow and unresponsive. You can turn this interface off and use the standard Windows Mobile interface instead. Making a call on the Touch Diamond requires that you dial a number with the on-screen keypad, which has large buttons and we found it quick to dial.

As with any Windows Mobile handset the Touch Diamond has a surplus of organizer and messaging features. You can manage your contacts, calendar appointments, and tasks from the device. These, along with notes, can be synchronized wirelessly via an Exchange account, or you can synchronize with Outlook on a computer. Email support is robust and the email client is simple to use. It can also be synchronized with an Exchange server, with emails arriving instantly, similar to a BlackBerry device. The lack of a real keyboard or keypad, however, does put a slight crimp on the device's messaging capabilities. We got our best results using a virtual phone keypad with predictive text on. The on-screen QWERTY was less impressive.

Windows Mobile also brings a wide selection of additional software, including Windows Media Player Mobile to handle your music and video playback functions. The software isn't as slick as the iPhone's, but it does the job well enough. The Touch Diamond has two web browsers. In addition to the standard Internet Explorer Mobile, HTC has also included the mobile version of the Opera web browser, which is set up as the default browser. Opera is a very capable mobile web browser that allows you to view pages as they would look on your computer and zoom in on the areas that you want to read.

Sprint's version of the Touch Diamond is locked to their network and their CDMA technology is not widely supported overseas, so this isn't a good choice for world travelers. As we mention above, there is an unlocked GSM version of the phone that will work on overseas networks as well as AT&T and T-Mobile in the U.S. On Sprint's network the high speed EVDO network can be used for fast data transfers and there's also Wi-Fi on board. Bluetooth is supported with a wide array of profiles including compatibility with stereo Bluetooth headphones.

Performance (read the full lab performance results at Wirelessinfo.com)
The Touch Diamond's audio quality was generally good. Sound received by the phone was generally clear and easy to understand. Sound sent by the phone had only a couple of minor problems, with lower frequencies slightly subdued and higher frequencies slightly exaggerated. This could cause your voice to sound a bit bassy or tinny, depending on how low or high it is. Side tone is the amount of your own voice that is piped back into your ear so you can judge how loudly you are speaking. On the HTC Touch Diamond, side tone was lower than we would have liked, which may cause you to speak more loudly than you should as you perceive your voice to be too quiet.

The Touch Diamond sports a 3.2-megapixel auto-focus camera that takes photos significantly better than the average cell phone. We found the resolution of photos to be very good, although the colors were all slightly inaccurate, something we've seen on HTC handsets before. You will have to wait for a bit for the camera, however, as the interface took a long time to come up and once in the camera application it doesn't capture images very quickly. What this means is you probably won't be able to catch that spur-of-the-moment shot that's only there for a second with the Touch Diamond. Video quality is reasonable for a cell phone, but don't expect to play it back on a television or even a computer screen with good results.

The Touch Diamond's small size does come with a cost in battery life. We found the talk time of four hours to be significantly below average and at the lower limit of what we would call acceptable for an average user. Music playback time was also below average at just below seven hours and web browsing time was the worse with the Touch Diamond conking out after only two and a half hours. We recommend you invest in a second battery or make sure you're near a charger if you want to get the most out of the Touch Diamond.

Comparisons (read more in-depth comparisons at Wirelessinfo.com)
In many ways the Touch Diamond is a device without a user, despite its wide array of capabilities. HTC's TouchFlo interface is supposed to make the touchscreen-oriented phone more usable, but frankly it's not as good as other touchscreen devices like the iPhone, LG Dare, or Samsung Instinct. For business users the software functionality is robust, but the lack of a keyboard will be a deal breaker for many. Perhaps the closest fit for the Touch Diamond is multimedia users. The camera is above average for a cell phone and the 4GB of internal storage means you can throw a bevy of music and video on there. There's a lot to like about the Touch Diamond, but in the end it may be a phone that just doesn't have a home.