Summary: I've had trackballs almost exclusively since I began computing 20(?) years ago. Started with Microtech. Eventually went with Logitech and am now using the Kensington Orbit. There is no trackball out there that is perfect. Few are even adequate. The Marble Mouse and the Orbit are both pretty good. A blending of the best features of both would come close to ideal. The Marble Mouse has good button positioning.
Summary: Reasonably priced and functional - a good buy, but design could be better. Footprint is excessive due to length of housing. Secondary buttons are too small and awkwardly placed for easy use. Best for using on a permanent work surface, not travel.
Summary: I bought this to replace my MS Trackball Explorer as it was the closest thing I could find. The ball is in the right spot, but the base is too narrow and uncomfortable there are fewer buttons, and I didn't even notice there was no scroll wheel until I opened the package. Disappointing would be my impression. However, it is much better than a thumb based trackball mouse.
Summary: When I was looking for a replacement for my Trackman Wheel trackball for my laptop, I knew I wanted another trackball. Since they don't move around like a mouse, I don't need as much space to use it. As I move my latptop around and use it in smaller areas, this is very important. I was dissapointed to find that Logitech no longer made the Trackman Wheels and the cost of a replacement was prohibitively high.
Excerpt: This is probably a good product, but I had to return it. It was so large, it was hard to use and cramped my hand. If you have small hands, you might try it before buying it. Maybe I could have learned to work around it, but after days, I couldn't get used to it and had to give up. Setup was instant and it had smooth motion. Ideally, the mouse would have had a horizontal scroll too - still looking for the right mouse to use all day.
Pros: Accurate Controls, Fast Response, Smooth Movement
Excerpt: Scrolling ball has a good size. Fair number of buttons. It looses two stars because it does not have a decent way to scroll. A scroll wheel or ring would certainly take this product close to the next level.
Pros: Ergonomic Layout, Fast Response, Smooth Movement
Summary: I've been disappointed as I read that it can`t scroll. Fortunatelly, buttons could be reprogrammed. I find that I don`t use forward button (little button on the right by default) so often, and I choosed "universal scroll" instead. After beeing reprogrammed, just press it brielfy and scroll by turning trackball. One leave this function simply by pressing button again.
Summary: I finally got tired of having to clear desk space for my Microsoft optical mouse, so I ordere3d this product when it was on sale. The ball part works just fine, but the switches need a de-bounce circuit. It seems to take 30% longer to read my email because I have to go to the Trash folder to retrieve about 10% of the messages inadvertantly deleted because of switch bounce.