I have one of the Combustion thermometers, and I like it. I used it more than I expected. In particular, I use it for roasting chicken and for sous vide things more than anything else. Then I got a Breville Control Freak, and I used it much less. :)

For maximum techyness, Combustion, Inc. correctly identified that sous vide is normally an overdamped system. If you follow their instructions you can increase the water temp some and then bring it back down in order to move the system closer to critically damped and speed up your sous vide.