Having recently reviewed the CF-29 and CF-18 I've become a real convert to touch screens, I love being able to just tap icons or drag windows around with my finger. The simplicity of using custom software with a touch screen just makes it all the more compelling. Of course you could just use a normal tablet PC for this kind of duty, but the CF-T4 has the added advantage of being a full ultra-portable notebook as well.
However, the CF-T4 does have one major disadvantage - it doesn't have an integrated optical drive. I'm not sure why the optical drive could not be squeezed into the CF-T4, but it's a real shame. Personally I would like to see a cross between the CF-W4 and CF-T4 allowing me to have the convenience of a touch screen as well as the integrated optical drive.
ToughBooks never come cheap, so it's no surprise that you'll have to dig pretty deep for the CF-W4. I managed to find it on Expansys for £1,764.95, which places it slightly higher than the Sony but considerably more expensive than the Fujitsu-Siemens. I couldn't find the CF-T4 on sale anywhere, but Panasonic gave me a suggested price of £1,807.15 - although to be fair, that's cheaper than the price Panasonic gave me for the CF-W4, so you may be able to find it cheaper on the street.
The Panasonic ToughBook CF-W4 is a great little ultra-portable notebook. The design and build quality are both first rate, while the novelty factor of the hidden optical drive is a bonus. Battery life is staggeringly good and exactly what you want from a machine like this. However, the price is high, the hard disk small and the lack of DVD writer may put some prospective buyers off.
If you're looking for a thin and light machine that can withstand the bashes and knocks of a life on the road, the CF-W4 will suit perfectly, just be prepared to pay for that privilege. That said, if Panasonic could squeeze a touch screen in as well, the price would be easy to swallow.