The author (Gary Krakow) names the HP iPaq H5450 'The killer device'. And it's pretty much it. It has everything a user wants, and more. Including built-in Bluetooth and wi-fi, beautiful screen, SD expansion and lots of memory.
The HP iPAQ H1910 is for the newbie user, and even so it's packed with features. A 250Mhz XScale processor, great screen and small form factor to help the new user get used to it!
