There are alot of big name companies that make it confusing and sell a high priced unit that does the same as lesser expensive units from sears or even farm stores. In some areas it takes more to "work" with the water to clean it - but that would not require a "name brand" unit to "fix" the water. All a softer does is act as a filter - the salt helps clean the filter media - its not complicated science . . . The media beds can become plugged up and may need replacing and the metering heads may need replacing. Neither job is hard - plumbing supply companies have access to those parts also. 

http://homerepair.about.com/od/plumbingrepair/ss/water_softener.htm