Any comprehensive study of the salt pool systems available today should begin with a comparison of the older analog models and the newer digital systems.  Recent developments allow these units to operate at salinity levels below the threshold of human taste and completely eliminate yesterday’s concerns of corrosion and stone erosion.  All modern units also have self-cleaning circuitry that minimizes the need for maintenance.  Beyond this, the single most important attribute of any system is the output, always measured in terms of pounds per day of sanitizer produced.  More is always better.  As for features, popular units all have warning lights that alert the pool owner of the need to add salt.  Some display the actual salinity level of the pool water.  Also popular is the Super-Chlor feature which provides a one touch method for temporarily boosting the sanitizer levels.  Good digital systems modulate the power in a way that maximizes cell-life.  Depending on the quality of the titanium cell plates, the various cells can now last between three and seven years with warranties to match. As with most electronics, the price of saltwater pool systems is not necessarily a good guide to quality or value.  The chart below provides all the details needed to make an informed decision.