All phone systems have exspectaions and limitations. One main factor you must consider if price is your concern, is the avaiablity of parts and its Resonable service life. Does the manufacture produce enough units to easily find spare parts 10 years later? Or will it be discontinued after 100,000 units. My point is simular to car buying. If manufactures sell a lot of a particular brand of cars then there will be alot of parts 10 years later. Find your local Phone guy and work with him. He may not sell what you think you want but will provide a solution to your endless needs and a system that he can suport. Depending on the type of business you are in can also be a key factor. Although, It may be your first phone system it won't be your last.