I have been using the Tc4400 for over a year now, and have optimized it to where it flies for me. I have a 1.83 mhz model, with 60gig drive. I have upgraded to 4GB ram, and run diskeeper in automatic, keeping the hard drive fully optimized at all times. I use an acoustic magic mic for lectures, and recognition at 20 feet is above 96%. It has been training itself to my hand writing, and I can write whole pages now without an error in onenote and journal. (You should see my chicken scratch...) The finger print scanner runs under the credential manager, and it manages security log-ons on numerous web sites, applications, or encrypted data files seamlessly. No problems there, and it is nice not to have to remember the various passwords!
The battery on mine is getting weak, on the downside, after only one year, but that is the only bummer. I have stayed with win xp, and will not upgrade to vista until its sp2.