Summary: The trackball body is a little larger than my full hand--the size is hard to discern from the photos. The buttons have to be pressed mostly in the top location. The scroll wheel does have a click function by pressing it in; I have not installed extra drivers and some Windows 7 apps respond to that...
Summary: I've been using trackballs for 20 years. I bought this since the box said it had 4 buttons. Who the hell makes a two button trackball? Two button mice are upgrades for grandma's Mac. Power users want at least 4
Pros: Very smooth ball. One of the smoothest balls I have used
Cons: Buttons are impossible to reach even with my huge hands. Only has two buttons. Makes this useless junk. DO NOT BUY! Your wrist will ache after 2 hours of use.
Excerpt: This trackball is the price leader in its category. Its main competitors are the Logitech Trackman Marble and the Kensington Orbit, both of which B&H also carries. The Adesso has a bigger ball than either of those, which counts for something with me, and it works with silky-smooth precision.
Pros: Looks Great, Smooth Movement
Cons: Not Ambidextrous, Tough To Get Used To, Uncomfortable
Summary: If you have big hands this might be usable. I'd definitely find some way to try it before you buy though.
Pros: Looks nice. Feels well built, if a little light.
Cons: It's not actually any larger than my dead Logitech T-RB22, which I was hoping it would replace, but it feels larger because it isn't ergonomically designed. You have to take your finger off of the ball to left click, which makes it impossible for gaming. Horribly uncomfortable.
Excerpt: It took a day or two to retrain my hand but now I am moving faster than I had with any trackball I've used before. Forefinger is for left click, middle and ring finger for the ball and little finger is for right click. Thumb is just for scroll wheel which I use a lot for CAD.
Pros: Accurate Controls, Easy To Clean, Ergonomic Layout, Fast Response, Smooth Movement