Logitech MX Revolution

The chief innovation of the MX Revolution is its scroll button. It functions in both the typical incremental click style, but also as a free-spinning wheel. This means you can whip the wheel frontward and back and navigate hundreds of pages in a document with a single spin. It's a little touchy when you zero it in on a particular page; sometimes moving your finger from it will make it jump another line or two, which can be irritating. But mostly, the free-spinning capability makes it much easier to scroll through long documents and Web pages.

In addition to the main scrollwheel, it also features a thumb-side wheel (the mouse is designed for righties). This side wheel acts like a rocker switch. It has a limited range of motion, but it's not designed for scrolling. It's meant to act as an application switcher. Roll it, and it brings up a small window listing all of your currently applications. You tap the wheel to move between them and press it to make a selection, at which point that app becomes your active window. It provides a remarkably easy way to switch between tasks, as long as your desktop setup is straightforward. On a system with two monitors and with multiple Firefox tabs open, we found keeping track of which screen was going to open up where a little difficult at first. Eventually, we got used to it.