I have been using the old iPAQ h6315 PDA phone for about the last three years.
While initially impressed with it's abilities over a regular cell phone, I quickly found out that the device was not as great as it was hyped up to be.
Service was terrible, thanks to the piggyback network offered by T-Mobile. The device's inability to get a signal, drop calls and perform other insane things due to firmware and hardware problems have left me with a less-than-satisfied impression.
T-Mobile quickly withdrew the device from the market.
What they should have done was have HP recall the device and correct the hardware.
Other than the above, I love the device. It beats the heck out of any ipod as far as features go, is way smaller than a portable DVD player or laptop, and the plan T-Mobile gives lets you have unlimited free data access.
The fact that I can have a phone, camera, GPS, watch hours of movies, listen to music, play games, chat, text, email, surf the web, watch photos, record voice notes, and keep a calendar, appointments, notebook, to-do list etc.. all in a single device that goes in my pocket has changed the way I live my day
...so long as the damn thing works and you can get a signal!!!