The problem I've found with laser mice is that being a person of limited reaction times, the mouse pointer, or targeting reticule in games, moves around faster than my feeble mind can cope with.
Now obviously this is a failing of mine, not the mice, but Genius' Ergo 525 actually provides me with the control that I need at the touch of a button.
The side-mounted DPI switcher moves between four points; 2000, 1600, 800 and 400DPI. This means that you can quickly decide which is best for you at any given moment.
This is by no means a new function, but the Ergo seems to work better than any example I've recently used. It fits snugly in the hand, is comfortable for long-term usage, the buttons are responsive, and the included mousemat offers a bang-on running speed. All in all, a good all-round package.