Kensington K644220 Orbit ADB Trackball (Mac)

Rating:
Summary: Cool looking; nothing special
Review: If you've ever used a trackball before, this is nothing different. The only thing about it that struck me as unique was the blue ball, and the erginomic design. All in all, it's not worth it's price.

Rating:
Summary: Well-made, great software, just try before you buy!
Review: Kensington's products are, in my experience, well worth the money---they are EXTREMELY well-made and tech support is top-notch. I find the Orbit very comfortable and the included software allows a lot of control and customization (I've used this trackball on both Windows and Mac OS). As far as physical quality of the product, only Logitech's input devices come close.

As with any input device, it's best to try this one on for size before you buy. I find it very comfortable and a good way to minimize joint-related problems in my right wrist and hand, but the only way to figure out whether it's comfortable for you is to try it out in person, preferably in a store where you can compare it side-by-side with other ones.