[replicant_argent]

5600 valves should be rebuilt every 2 or 3 years for optimal performance, in my experience, while not the "best" valve out there, they are relatively cheap to purchase. A rebuild of the valve takes 40-ish minutes (being meticulous) or less (if you are handier) One of those "you get what you pay for" products. If you add up the maintenance costs over a typical service life, not the best value, but that depends on your priorities, such as budgetary, expected time you will own the home, etc.
If you find someone locally that carries Capital valved equipment, and has been around for a while, and uses high quality resins that agree with your local water chemistry instead of a generic resin, and the price isn't beyond value, you should be good. 20+ years before a rebuild wasn't as all uncommon IME. High quality valves and controls, the timers and motors gave very good service as well, occasionally a meter dome would need replacement, so if a calendar system would work for you, that is the most trouble free, I think. (barring power outages)