Are they worth the price... That is an interesting question. In comercial and industrial application they certainly are. In a situation where you are dealing with tens of thousands of dollars a month in electric, they can make a considerable difference. When you get them in the relm of residential, I think they are still in the "developing technology." I cannot service a freq. drive with out having my laptop to communicate with it, so your servicing cost just soared. As HKestenholz
mentioned, most of your residential techs do not have the tools nor knowledge.