When comparing Roccat Tyon vs Kensington Expert Mouse, the Slant community recommends Roccat Tyon for most people. In the question“What is the best gaming mouse?” Roccat Tyon is ranked 27th while Kensington Expert Mouse is ranked 55th.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Many keys, 1D analog stick, illumination, good sensor

Pro Full Linux support
Roccat has good Linux drivers.

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 No MAC OS drivers available
This is a common con for many gaming mouses. But since the mouse buttons can be bound to direct input events, lack of drivers can be overcome.
Con Functions cut down if not using Roccat keyboard
There are extra features with the Easy-Shift[+] thumb button but a Roccat keyboard has to paired with the mouse to utilize them.
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.
