I have tiny hands and find it really easy to use. Also, scrolling is a doddle. Use one finger to hold down the left button and another to roll the ball up and down to scroll.
I previously had the Kensington trackball elite at work, and despite regular cleaning, the rubber rollers got too clogged up and it stopped working. I'm really pleased that this is an optical mouse and I no longer need to keep on trying to clean the rubber bits, which was really fiddly.