Summary: I have owned and used Trackball Explorers for close to 10 years now. There is simply no substitute. I have two of these warriors on my desk, they have never let me down. My PCs have changed but the Explorers have not. I don't travel with them any more since they are now so rare and valuable.
Summary: It's now 2015. I bought my Microsoft Trackball Explorer in about March of 2001, making this device almost 14 years old! I love it as much now as I did then. It has outlasted two keyboards and three -- yes three -- computers.
Summary: Replacing identical unit received as present; previous one used too much battery, retainer piece on bottom lost its ability to stay secured, and finally began to not move the cursor properly some of the time. New one works fine, we'll see on the other things.