I honestly don't have anything bad to say about this trackball! I have been using it for work for the last 3 months and the rolling mechanism really broke in nicely. The roll is smooth and the profile is very comfortable for me and the way my desk is set-up. Scroll wheel is easy to use and works perfectly! I would suggest this to anyone who is suffering from carpal tunnel and needs something more ergonomic. I have been having wrist pains from my constant clicking and this has alleviated my pain for the most part.