I have terrible Carpel Tunnel Syndrome in my right hand, so bad that I can't use it for mousing at all. Over the years I've used several different so called "ergo" type mice that never really helped until I found this one.
The expert Mouse by Kensington is highly adaptable; it's programmable so you can customize it to work the way you work. The trackball is located in the center and is 2 inches in diameter; you move it by either turning the ball with your fingers or your palm. There are 4 large buttons that can easily be programmed to be the one click or double click button by going to the customize part of the software; it's very easy to do. The software is very easy to work, you basically don't have to do a thing and it will still work based on the company presets but if you need to customize it, you can and you don't have to be a computer guru to do it.
Currently I have the mouse set up to use with my left hand; it was very easy and because of the way it is designed, I easily adjusted to it within a couple of days. The software also has a feature you can activate to remind you to rest your hands or take a break every 30 minutes, which can get annoying over time.
However, the best feature on this mouse is the scroll wheel, best thing ever! I work with a lot of large pdf files, scrolling through them used to take a lot of time but now, I just use my fingers to scroll through them FAST. A quick flip of a finger and the wheel is just spinning right down to where I need it to go. I can’t imagine having to work without the scroll wheel, it’s such a great feature!
The one thing that isn’t that great is the wrist rest; I’ve had to add additional padding to it because it caused some pressure point issues. Another person I know removed it as it caused his hand to hurt. Additionally, this mouse is big; it won’t fit on a standard mouse tray unless the wrist rest is removed.
If you have nad or writst problems, this is the mouse for you; if you want to avoid wrist problems, then this is the mouse for you too!