The mouse fit my hand well (I wear a men's size large glove); it didn't feel too small and cramped or too big. The mouse itself is made of hard plastic with a rubberized grip that gives it a slightly cheap look and feel, but it held up well during the two weeks I used it.
If you like to change the tracking speed based on the software you're using, you'll find the mouse's ability to instantly switch tracking speed very helpful. On top of the mouse is a diamond-shaped button that lets you switch between three tracking speeds. To indicate which one you're using, the button lights up; the brightest light means tracking is on the fastest speed, no light means it's on the slowest speed, and a medium-bright light means the mouse is set to the middle speed.
(Image Caption: Verbatim's software enables you to customize the functions for each mouse button.)
Unfortunately, there's no battery life indicator to tell you when the AAs inside the mouse need to be replaced (Verbatim includes a pair of alkaline AA batteries). The included USB receiver is about the size of a USB flash drive. I didn't experience any signal dropouts during my testing, and I was able to use the mouse without any problems. You can always use the On-Off button to preserve battery life.