I have tried other brands and had so-so results. The Kensington Optical Mouse is the first one to provide razor like accuracy. I play a number of games on my PC and there is nothing more frustrating than a wandering mouse. This mouse is not a wireless mouse.

The trackball mouse is designed to be an alternative to the traditional mouse, with the cursor controlled by a large weighted ball. The ball itself is approximately the size of a snooker ball, finished in a sparkly grey effect.

Excellent precision and comfort; symetrical design for left and right hand use

Not as smooth to navigate as advertised

This trackball-style mouse is a credible alternative to the traditional mouse, using a large weighted ball.

This is excellent for people w/ carpal tunnel or other "grip" problems. The grooved circle around the ball is great for scrolling. Regular mice strain my thumb & wrist. But if you need a mouse for gaming, this is not it. The gamers in my house hate it.

Ive used the various incarnations of the Kensington Expert Mouse for nearly as long as Ive used a pointing device on a computer yeah, I was a late adopter of Windows, I held onto DOS as long as I could. No mice needed with DOS!.

Large ball; smooth motion; easy to clean

Hard to find out there, except for some specialty stores, or on line; Misleading name! Why is it called an Expert Mouse ..; when its a trackball

We've used Kensington ExpertMouse trackballs for nearly 20 years. The large ball, handy button shortcuts, and longevity have all been big plusses. The trackball beats a mouse for many of us based on personal preference, and features such as occupying limited desk space compared to the room a mouse...

same timeless trackball quality; lots of configurable buttons; kensington's traditional quality

scroll wheel feels cheap; no wireless model anymore; scroll wheel is a hit on traditional quality

I was pleased with the trackball, as many of the people in the post production industry use it. I was very happy with Kensington supplying a wrist rest in the box. The motion of the ball is very smooth and highly accurate.

Easy To Clean; Ergonomic Layout; Smooth Movement

BUttons

Bought two. Been using this for years after some elbow pain using regular mouse. No more problems & large ball is easy to maneuver. Plug it in & it works.

This is the eighth Kensington trackball device that I've happily owned over the last 20± years. Having just purchased my 10th Mac-the new iMac 21.5", 3.2 GHz-I naturally "tried" Apple's new wireless bluetooth mouse.

PROS: Large ball, smooth ball movement, comfortable design, large programmable buttons with great software, scroll wheel great IDEA. CONS: Tracking slightly jumpy at times. Scroll wheel is such a terrible design it feels and often acts 'broken'. Reviews are correct about the scroll wheel.