I'm writing this review in 2014, many many years after this device has disappeared from the company's product lineup. I can state that this is the best input device I've ever used. I've owned several, and had them on my work and home computers for very detailed CAD, 3D modeling, and precision Photoshop work. The downside with this (and any trackball or mouse) is that dust accumulates inside the housing but this is super easy to clean when it does. I occasionally think about replacements, even though it looks funny, even outdated, no one makes a "fingertip" controlled trackball with ergonomics quite like this so I stick with it. Logitech if you're out there, please bring us a modern version!!