Just for the heck of it, here's my TC4400
next to an X61 (running Windows 7 and Windows 8 respectively):
The TC4400 was the tablet version of the NC4400, and was almost exactly the same, except for the screen:
It's interesting to compare the two machines. They're both 2ghz Core II Duos. HyperPi takes 1m 02.083s to calculate pi to two million digits on the X61, 1m 04.334s on the TC4400. They both have 1024x768 4:3 displays, a fingerprint reader, a pointing stick. I tend to use use the X61 more often because it's smaller and lighter (and it has an SSD in it). Tablets really need a 1600x1200 screen, 'cause most websites don't look too good with a horizontal resolution of only 768 pixels. As you can see from the picture.
I've never used a PC tablet before. The pen works very well as a pointing device, and it's great for music applications (lots of dials and buttons) and websites like Imgur, where you just graze on links. In contrast the emphasis on handwriting recognition as a means of controlling a PC - which seems to have been an obsession with some technologists for decades - feels totally misguided and doesn't work. And as a point-of-sale or data entry tablet the TC4400 is just too bulky to carry for any length of time. After having used it I can understand why modern iPod/Android-style tablets are popular; just like the old Palm Pilots, they don't try to do too much.