Summary: If you press caps lock twice, it triggers a profile change and also freezes your mouse until you press caps lock one more time. If you use the caps lock button for voice chat, you'll be unable to use these mice without forcing yourself to change your voice chat hotkey. Do you ever accidentally press caps lock? What's the first thing you'd do? Press caps lock again to turn it off right? Oh, you just changed your mouse profile and locked up your mouse.
Summary: We got one of these and it would work great, then suddenly the cursor would race across the page and stick. After restarting the thing a few times we sent it back and asked for a replacement, since it was really good when it did work. The replacement just came today (kudos to Amazon for amazing service). This one doesn't work at all. In fact, you can visualize the laser component up inside and to the left of the 'eye' in the housing.
Summary: The cursor won't stop moving when I try to point it at anything. It won't stop moving after I remove my hand from the thing. I recommend the Equalizer, which hasn't failed in over a year of heavy gaming. This one's being returned and I'm ordering another Equalizer.