For years I stuck with my Nokia 9110, without upgrading, because I couldn't move to a Treo-sized keyboard. On my 9110 I wrote a whole book, several magazine articles, and lots of e-mails, all while I was riding the bus. Then I saw the K-JAM and decided that the keyboard was usable enough to move to. Before I bought a K-JAM, I saw articles about the TyTN, which I've now bought.
First impressions are great. All I've done so far is get the phone running on my old SIM card and gotten the Wi-Fi connected to my home network. Both took a matter of minutes.
More later as I get more of the PDA's features running.