I can't speak to the TX as I haven't spent time with one. My favorite in the ultraportable space is the Fujitsu P7020D. I have one, I utterly abuse it (it stays in my backpack and gets thrown around as a carryon constantly) and it's worked flawlessly. It's built well and the BEST part about it is that the hard drive is easy to replace should something happen. One downside to the Sony machines is that they're quite difficult to disassemble.