Very cool, equus! I just played with one at our local AT&T store (it was the manager's, they only got one in for sale that's being held for someone). It's quite small and reasonably fast too. The manager said that he'd had his for a week and it tended to hang during calls requiring a soft reset. Sounds like yours behaved better, other than poor reception. Compared to the other phones in the store (Nokias, Treo 600) the PPC4100 did have weaker reception: 1 bar vs. the other phones' 3 bars.
If one is a heavy Pocket PC user, it might be hard to get used to a unit that has no application buttons and no d-pad!
I'm so surprised and disappointed that the AT&T version doesn't have the keypad flip-- it's such a good idea (adds screen protection and easier dialing). That flip really would've helped differentiate the model!
For those who are interested in buying it, it supports both US GSM bands (850 and 1900 MHz) and 1800MHz (commonly used in Asia) but not the 900MHz band used in Europe.