Easy to use. Fits a multitude of hand sizes. Hands range from my eight year olds to my sixty year old father in law. For the price this is a great computer mouse. It is cordfree and always ready for use. Performance Never had a problem with this mouse. Works great and is very smooth on the mouse pad. Durability My two boys seem to drop it every week at least once and it keeps on working. Design Easy to use. Fits a multitude of hand sizes. Can be used by either right or left handed people. Comfort I am on my computer five to six hours a day seven days a week and my hand is never tired or cramped from using this mouse. I personally feel that this mouse is intended to provide optimum comfort and avoid injuries such as carpal tunnel syndrome, arthritis and other repetitive strain injuries. I have no problems and as previously mentioned I have no problems. It feels like it is designed to fit my natural hand position and movements, to reduce discomfort.