The analog 5600... I doubt that there is a more reliable, simple, or longer lasting valve on the market. It has been a favorite for the light commercial market for decades. The Big Box store units are simply the lowest bidder wins softeners, and many are now looking to some even lower end overseas manufacturers in order to be $5 cheaper than they are now. I would not compare the Big Box Stores to a Schwinn, that is why I used Huffy, they are literally as low cost as they can be. I stopped servicing them years for many reasons. A Fleck, Clack, or Autotrol based unit is a great balance of price and quality. And like the op's system, they will last for decades with little service. The 5600 Electromechanical system is the most bulletproof design available, my main problem with them is their lack of adjustability and lack of diagnostics, but sine they rarely break, diagnostics are not that important. The 5600 is rebuildable in 5 minutes and you don't have to worry if it is going to work, they always do. Its only real weak spot is the 24 volt motor, but these usually last 5-15 years and are replaceable in a matter of minutes.
I am not bashing the systems, only pointing out some things to consider when purchasing a softener. Just look at the other major appliances available at the big box stores, most of them have their range from the very low end/lowest price, to the high end. The softeners are available as only the lowest prices version, and usually a slightly larger version with all the same low parts.
