The big box store brands usually only last 2-5 years before they break. They are all cabinet models, meaning the resin tank is inside the salt tank with a cover over everything, and that makes them difficult to work on. Regular softeners have the resin separate from the separate salt tank. Another thing is the limited size of cabinet models, max is 1.2 cuft of resin.
Do you want to be dependent on Kenmore service or do you want to be an independent DIYer and install and service your softener yourself?