I have had an opportunity to use Microsoft’s Voice Command software for Windows Mobile 2003 for a couple of weeks now. I do not think it is worth the $40 price tag for those who don’t use a phone edition device.
The built-in microphone on my iPaq 3970 does not recognize well enough in my car to provide accurate recognition. I believe this limitation would have a better result with a headset and microphone that can be used on the phone edition devices. It is still better than having to look up the contact with the stylus while driving, but it requires multiple attempts almost every time.
I am interested if anyone else has had a different experience.