Thanks to a severe flare-up of Carpal Tunnel Syndrome, I found myself in a lot of pain after a day of typing.  I finally broke down and bought wrist wrests for both my keyboard and my trackball, and I'm glad I did even though both took some major getting used to.  The keyboard rest is great in most respects, but for me it has two drawbacks:  It could be a bit longer, and it pushes the top of my keybard up under my desk (I have a pull-out shelf arrangement.)  Neither is the fault of Fellowes necessarily, and I mention it only to alert anyone who has a very wide or deep keyboard to these possible (minor) problems. I do find, however, that the rest isn't quite high enough for me to avoid some stressing of my wrists.