In general, it's convenient. The hand is resting. I took it in addition to the mouse, under the left hand, so as not to raise the right one from the numbers. I took this model as an inexpensive one for testing. It turned out to be a very convenient size for my small hand, I am right-handed, but there were no special problems with the control of my left hand. The ball is large and comfortable. Not enough scrolling, forward and backward buttons. For me, this is not a complete replacement for the mouse, but an addition to make me less tired.