In my past experience the Sun optical mousepads worked OK in single user environments, where people kept the pads undamaged and clean. Generally, in 1993 if you worked for a university or company that cared to put a $5000 (in 1993 dollars!) computer on your desk, you would treat everything associated with it with care.

They worked considerably less well in university shared computer lab environments where the pads were subject to more wear and tear.