Though we found the Arc Touch Mouse's scrolling generally effective, it's still easy to lose touch of the tab. We also had two brief instances in which half of the tab stopped responding, although in both cases it woke back up in less than a minute. Neither annoyance is a problem with the actual physical scroll wheel, and thus we still prefer that design--Logitech's especially.
Otherwise, from an interface standpoint, the Arc Touch Mouse behaves like a regular mouse. Microsoft's proprietary BlueTrack laser sensor gives you responsive cursor movement that you can use on a variety of surfaces. Sadly, you get no thumb-side buttons on the Arc Touch Mouse, which we've come to consider indispensable for moving backwards and forwards while Web browsing. Perhaps to make up for the lack of a back button and the absence of a middle mouse button, the mouse allows you to program the scroll tab within the software to act as a button, but that's hardly a replacement.
Aside from the touch scrolling, the Arc Touch Mouse's other unique feature is its collapsible design. The body of the mouse is wrapped in thin black rubber, but inside is an articulated frame that you can snap into either a curved or flat-lying position. Microsoft markets this adjustable design as a benefit to travelers, and perhaps if you have a particularly cramped laptop bag you might appreciate it. The mouse also powers off in its flat mode, ensuring that you won't accidentally drain the pair of included AAA batteries.
Despite the Arc Touch Mouse's distinct benefit for travelers, the paired -down design has a certain flimsy feel to it. Your reviewer has only modest-size hands, but the mouse still felt like it was too dainty, and I never felt the same surety of cursor control that comes with the heft of a traditional desktop-size mouse. That's a subjective judgment, of course, and perhaps my opinion would change after using the mouse for an extended period of time. For now, I still prefer the Logitech MX family of mice, of which the MX 1100 is closest in price to the Arc Touch Mouse.
Even if we're not completely enamored with the feel of the Arc Touch Mouse, the setup couldn't be easier. You simply pop in the batteries, connect the tiny USB RF receiver and you're up and running. If you want to make any of the customizations we've mentioned to the scroll speed, the scroll button assignment, or others, you can download the settings software from Microsoft's Web site.