I have had at least 4 other Tracball's, I think their GREAT!!! The only problem I had with this one was, the Marble kept falling out all the time... I would be using the tracball and if you moved it to fast it just would pop out... If you tipped it on the side or over the thing would go rolling across the floor... It could be quit irritating... It looks great, it is the best looking one I have used, the Marble look of the ball is really much nicer than the red ones..... Just how lose the ball is, NOT GOOD!!!!!