The water softeners you buy at Home Depot/ Lowes will do just as good of a job as that 5000 rain soft. the salt is cheap, and when it flushes it really doesnt use that much water. Salt is cheap as hell too.
some of the advantages you will notice with a water softener are less hard water spots/calcium deposits/ iron deposits/ etc. on your dishes, shower, sinks, and toilet. The one thing i dont really care for with a water softener is when you are first getting used to it, when you take a shower you will feel "slimy". that is because you are actually washing ALL the soap off your body. hard water doesnt get all the soap off and thats what gives you that dry feel ( i guess is the best way to describe it).