Others say...

"A Good Buy"
I'm working in a limited space and the Kensington Orbit makes the situation a little more comfortable and at a reasonable cost. I've used Orbit Optical's big brother Kensington Expert Mouse Optical USB Trackball for PC or Mac 64325 and I prefer the smaller version.It's simple and it gets the job done it's a nice easy little product, HOORAY.

"Gets the job done"
I owned the older model before but it finally klunked out and was time to get a new one. (Old one was 6 years old). The ball glides more freely and do not get the dust build up on the sensors like I did with the old one. I had to use an optical mouse while waiting for this to arrive. I had aching wrists every night. Now I am back to my normal happy wrists again. I would highly recommend it to anyone who has to do detail work and finds optical mice cumbersome.

"Great Product but no support for Mac users"
The readme file never mentions this mouse and the techies in Bangladesh are courteous but clueless as to how to change the default to left hand use. I considered returning it but didn't want to give up since I liked the feel and look and held out hope of finding a way to replicate the scrolling features offered by the Mac Mighty Mouse - but for the left hand.

Emailing Kensington about the product merely yielded their advice to call them but even that didn't help until I figured it out for myself for which I kept one star for myself as a reward.

There are complaints that the ball falls out (as opposed to the parallel Logitech Marble Mouse...) but that's unfair since there's no need to pick it up and turn it over. The red glow of the ball is a nice touch as is its 2 inch size which is not mentioned in the tech info.

Amazon needs to design a better order form, one that includes precise instructions on how to fill it out if both US Postal Service AND private carriers are involved in the shipment and delivery so that PO Box holders do not suffer delays when the post office receives parcels addressed to a street address and the clerk does not know the recipient's box number. That's particularly critical where delivery and billing address are different.

"Super Durable"
I have been using this mouse (the *same* mouse) for over five years. There is a spot on the left button where it has become worn from my thumb clicking. I'm a Web developer so I use this mouse pretty much continuously--at *least* 8 hours per day, 5 days per week. It has performed flawlessly since day 1. It is so comfortable and I have used it so long that it feels like an extension of my hand.

Also, I have always used it on a Mac. The Kensington Mouseworks software has performed flawlessly as well.

I highly recommend it.

"Plain and simple... "
Had an old Kensington Serial ball mouse (yeah im old). well MOBO's really dont come with serial ports anymore, and this old friend just was working anymore. It was the one with the cue-ball, large and awsome. Well here comes the predessor.. and I got to say, 3 years going with the child and its simple and easy to use... if your 40 something and want the past back, go for this pup.