They don't use standard Honeywell zone valves?
They are not the thermal zone valves but moterized and somtimes the
return spring will stick.

Can't say about the savings as our house is about 100 years old and the
old boiler was just about as old. previous owners gave us the oil
bills from the year they moved out. Before replacement we had an
electric water heater after new system the EK provied hot water.

As for adjustment and relilablity never had a problem, sounds like he
doesn't want to send his crew to the traiining EK provides.