The HTC Touch Diamond is evidence that interface is king. Well, actually, the iPhone proved that already; the Diamond just confirms it. Though most users have not even seen one in the flesh, many are already heralding it as the one to beat after seeing videos of its TouchFLO 3D interface. Here's our take on this PDA-phone.

Design

Size-wise, the Diamond is very handy. PDA-phones are often guilty of being too wide, but this one has no such problem. If you look at the left and right sides of the display, you'll notice there's hardly any wasted space--the Diamond's horizontal dimension is just a touch wider than the screen's width.

The prism-like back cover of the Diamond.
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Here's a brain teaser: How many corners will a rectangular block have if you cut off four of them? The answer to that question will give you a rough indication of what the back of the Diamond looks like as the four corners of the battery cover seem to have been lopped off--which fits in with the back surface's undulating prism design. Though HTC's photos and renderings show the feature quite obviously, we have to say it's not that striking on the actual device. It's not one of those things that make you go "yuck" for trying too hard and is quite tastefully done. The Diamond uses a glossy plastic material for it body, which leaves ugly marks if you have sweaty palms and nasty fingerprints.

As mentioned, the front of the Diamond is taken up mostly by its VGA display. Below that, you have four buttons and a directional pad. At first glance, you may think these buttons are touch-sensitive because there is no physical separation between each one and the entire surface is flush with the screen. It is true, the panel is touch-sensitive, but each button is depressible as well. The touch-sensitivity part of it comes into play only in specific situations, like when you want to use the directional pad as a scroll wheel. These shortcuts and selector button work fine, but we would have preferred if the four directional buttons around the selector were larger.

There are few buttons around the sides of this handheld, just the volume control on the left and power on the top. Keeping with the clean, uncluttered design, there is a single connector on the bottom, a mini-USB one for charging, syncing and connecting a wired headset.

Features

By far the greatest innovation of the Diamond is its TouchFLO 3D interface. A dock at the bottom of the screen divides the Home screen into different sub-menus, the default one showing the clock, call history and upcoming appointments from the calendar. Moving to the right, you get quick access to other commonly used items like quick dial, messages, MP3 player and a settings page. Every item is beautifully rendered with transitional effects. For example, in the text messages section, you can switch between SMSes by swiping up and down with one finger. Words float up or down, displaying also the sender and time of message. To reply, you tap on the body text and the screen will switch to the default Windows Mobile 6.1 threaded SMS interface.

Aside from the "I can't believe it's Windows Mobile" Home screen, the Diamond has a few other useful conveniences. For example, if your phone is keylocked with the screen turned off, pulling out the stylus will turn it on, ready for use. That's quite clever because it's natural to have your phone turned on when you take out the stylus, aside from the times that you merely wanted to use it to scratch your heel without removing your shoes.

Inside the Diamond is an orientation sensor which knows how you are holding the device relative to gravity. One way HTC has put that to good use is when a call comes in while your phone is on a table--you only have to turn the screen face down against the table to mute it. Note though, that this isn't a revolutionary feature as it is found in some Nokia devices like the Sapphire Arte. This sensor also orientates your display when in the browser and works in a bundled game called Teeter which requires you to navigate a steel ball through obstacles into a hole.

Aside from reorienting a page, HTC's custom browser for the Diamond has many other features. Built in cooperation with Opera, this browser renders HTML pages in their entirety, allowing you to zoom in to specific areas when you want to read them. The interface is fingertip-friendly and pages go into full-screen mode by default when they have finished loading. Pages like Gmail work as they would on a desktop browser, which is very impressive. One downside is that HTC has implemented Adobe Flash Lite 2 instead of the latest version 3 in the Diamond, which means that when you visit sites like YouTube and Vimeo, the videos won't appear on the site as Flash Lite 2 doesn't support the FLV format videos used by such sites.

As a workaround, HTC has provided a dedicated YouTube application which allows you to search and view any YouTube clip. This application is very well-designed and we found the video quality to be excellent on the Diamond's VGA display. If you are wondering why you can do this on a dedicated application but not in the browser, it is likely because the YouTube app has its own FLV decoder that doesn't work in the browser. Case in point, Windows Mobile users in the know have been able to stream YouTube videos using the open-source program TCPMP with an FLV plugin for sometime now. Essentially, what HTC has done is to reproduce what TCPMP has been able to do but with a more elegant interface.

The Diamond comes with some custom text input methods including a full onscreen QWERTY keyboard, a phone keypad and a compact QWERTY method which puts two letters on each virtual key. While they are all great alternatives to the default Windows Mobile text input methods, they each take up more than half the screen. This allows for easy finger tapping, but often covers the text field which you are typing into so you can't read what you are keying in. This needs to be addressed in a future update as it can be quite annoying.

Connectivity-wise, this handheld comes with HSDPA which supports transfers up to 7.2Mbps. The Diamond has all the requisite wireless radios like Wi-Fi and Bluetooth and also includes GPS for satellite navigation. The processor found in the Diamond is from Qualcomm and has a clock speed of 528MHz. It also has a separate video processor, necessary to render all the fancy graphics in TouchFLO 3D. For that reason also, you won't be seeing this new interface as a firmware upgrade to the regular TouchFLO in older devices like the HTC Touch Dual.

The Diamond comes with 4GB of storage memory aside from its 192MB RAM for running applications and 256MB ROM. There is no expansion slot for your own microSD card, something HTC left out because it would increase the bulk of the device. While some may not like the idea that they can't swap out memory cards, 4GB of internal storage should be sufficient for most users.

Performance

The Touch Diamond comes with a 900mAh battery. There were doubts about the stamina of the device and, after our experience with it, there may be reason for concern. We got less than two days of use. This included occasional voice calls (nothing we would rate as heavy usage), less than 20 minutes of Wi-Fi surfing, no GPS use and about 15 minutes of HSDPA data transfers. We're pretty sure that someone who uses the phone for business and gets phone calls all the time will have to charge it daily or buy an optional car charger to keep the Touch Diamond in operation.

Voice quality is excellent and the speaker phone is quite loud, good for video calls and for hands-free use when driving.

The rear camera is a 3.2-megapixel one with autofocus, but offer no LED for dark situations. One interesting feature of the camera is that when you place your finger on the selector, it starts to focus the image, similar to half-pressing the shutter on a real camera. Depressing the button will then take the shot. Image quality is fine with reasonably accurate colors.

A test shot from the Diamond's camera. No editing done except for resizing.
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In our use, we managed to crash TouchFLO 3D a few times. It's not uncommon for applications to shut down unexpectedly and occasionally in Windows Mobile. To HTC's credit, we did not encounter any instability that could be considered crippling to the entire user experience. The Diamond may have more RAM than any other Windows Mobile device out on the market now, but TouchFLO 3D is very resource-intensive and we felt the system slow down a couple of times, especially when there were other CPU-intensive applications running in the background. Otherwise, it worked smoothly most of the time.

Conclusion

Many readers have emailed us to ask how the HTC Touch Diamond compared to the iPhone 3G. We could go on and on about that, but the main difference is this--you can buy the Diamond now, and HTC doesn't require you to fulfill its terms to own one. Just fork out S$1,098 and you can buy one unlocked, without an operator contract. The little improvements HTC has made to the Diamond make it a great product compared to all the other keypad-less Windows Mobile PDA-phones out there now. The less-than-stellar battery performance and resource-hungry TouchFLO 3D interface (which can slow down at times) are the only concerns we feel one should look out for when deciding whether to purchase it.