Ranked in these QuestionsQuestion Ranking
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.
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.