I am a 25+ year technician and will not, nor have I ever touched the Kenmore softeners. I would recommend a Fleck, Autotrol, or Clack based system. No cheap imports or big box store units. Most of those are "lowest bidder wins" units.
The unit costs have gone down since they only push price. It is a race to the bottom with many of the water treatment units. Remember the race to the cheapest cars in the 80's? Hyundai, Yugo, etc... The cars kept getting cheaper, and worse.
Spend a few extra bucks and get a high end unit.
Send me a PM, I know several companies locally that will get you a good deal on a real unit.