When comparing Mad Catz RAT 7 vs Kensington Expert Mouse, the Slant community recommends Mad Catz RAT 7 for most people. In the question“What is the best gaming mouse?” Mad Catz RAT 7 is ranked 37th while Kensington Expert Mouse is ranked 55th. The most important reason people chose Mad Catz RAT 7 is:
It will still work just as well as the day you bought it.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Reliable; keeps on going through the years
It will still work just as well as the day you bought it.
Pro Incredible flexibility
Many parts of the mouse are adjustable with interchangeable pinkie grips and palm rests to a custom weight system. The mouse is able to literally change its size and weight.
Pro Cordless version available
It also comes in a cordless version, called the RAT 9.

Pro Comfortable and ergonomic
With thumb and pinky on the buttons and three fingers controlling the ball, the user's wrist lays flat on the table (or on the provided attachable wrist rest).

Pro Intuitive link between ball motion and FPS camera angle
The ball is large enough for turning it to feel like physically rotating an object.
Cons
Con Laser (not optical) sensor
Laser sensors are just not that great when compared to optical sensors. Often there is acceleration issues with laser sensors.
Con Expensive for what the internal hardware is
Sadly the components inside of this mouse are pretty cheap, ranging from the switches to the laser sensor. For the price Mad Catz is charging one should expect higher quality components.
Con Forward / back buttons wear easily
The two buttons located on the side of the mouse (sometimes known as the page forward and page back buttons for internet browsers) wear out easily after only a few months of usage. That means that it requires extra force to register a button press, all while receiving no touch (or audible clicking) feedback. Frustrating but the mouse does continue working.

Con Uncomfortable "seam" where your thumb and palm meet
Con Not a mouse
This is a trackball, not a mouse.

Con Questionable secondary button defaults
The upper left button, which is the hardest to use, is middle click by default. The upper right, which the ring finger naturally rests near, defaults to Back. This can be particularly annoying as the Back button is easy to brush when moving hands between keyboard and mouse.
