The Speed-bloc is very well built and much quieter than ordinary palm sanders.  It does an excellent job and due to it's lower than normal vibration, doesn't put your hand to sleep in the process.  This machine is comfortable to grip and the on/off switch is conveniently located.  Changing paper is quick and easy (with or without the little tool they provide).  The Speed-bloc is an excellent old design that Porter-Cable was smart enough to leave alone.