Obviuosly, if they work, they are worth it. If they are not working, are they worth fixing? That is another question.
There are many Rainsoft customers on this forum;most here due to problems with the units and other difficulties. Find out if the units are working and where a service tech can be located--if locally.
If your system is a "timer" unit, I would get rid of it. Rainsoft still often sells timer softener, which are very inefficient. Their RO is very simple in design and apples-to-apples competitors may serve you well. Going new with drinking water systems is preferred, IMO.