On the plus side, HTC has taken onboard the complaints about the Touch Diamond's non-standard audio jack and instead kitted the HD out with a standard 3.5mm headphone socket. It'll certainly be put to good use as the stereo headset that are supplied in the box are pretty poor as they drum up about as much bass as a portable transistor radio. As the handset also supports A2DP you could always stream music over the air to a Bluetooth stereo headset if you prefer.
Call quality certainly wasn't a problem during our test period with the speaker and mic delivering crystal clear voice quality. However, battery life wasn't so hot. We got about a day and a half out of it with mid to heavy usage for phone calls, web browsing over Wi-Fi and use of the GPS receiver.
The most telling thing about the Touch HD is that everyone we showed it to asked why Google didn't use this as the phone to launch Android. It's a question that's difficult to answer as in terms of hardware this is unquestionably a brilliant device and with a decent OS it could have been a serious challenger to the iPhone. However, in its current form it's merely the best of the also rans, but that still means it's one of the best Windows Mobile device on the market at the moment.