ELECOM EX-G Wired Trackball Mouse, Ergonomic Thumb Control, Smooth Tracking Roller Ball, 5 Programmable Buttons, Tilt Scroll, Computer Mice for PC Mac

Customers give positive feedback about the trackball mouse's build quality, comfort, and button responsiveness, with multiple profiles for various types of programmability. The responsiveness and smoothness receive mixed reviews - while some find it exceptionally smooth, others report the ball doesn't move smoothly. The ergonomics and reliability also get mixed reactions, with some finding it ergonomically comfortable while others say it fatigues their hand, and while some report it works well, others find it unusable for their needs. The ball stickiness is a significant issue, with customers reporting it gets stuck and won't roll smoothly.