We have used LINK Systems from Applied Computer Systems here at SUNY Oneonta for many years in several computer labs. They have had the desired effect of giving the instructor control of the student monitors, so the instructor can focus student attention where he or she wants it. The system is very intuitive to use and so, requires little to no training. These systems have been very dependable and for the few times we've needed it, ACS support has been very good. We are currently in the process of converting from the hardware based LINK systems to the ACS SoftLINK software based system and are having the same success with that.