@trustedlawyer - I have no experience with Hunter, but Rachio has worked well for me and the company has been very responsive to feature requests and the icing on the cake is this community where there is a wealth of information from folks that aren’t employed by Rachio. I don’t know what the water cost is for your installation (i.e. city water at $/gallon or well water paying for pump and maintenance, etc.), but I think the two Rachio units would pay for themselves over four independent dumb controllers.
Without more information about the setup (e.g. watering restrictions, water supply capacity (i.e. can two zones be run at one time), water pressure, head type (rotor vs spray vs drip), etc.) it would be hard to make any recommendations. One option would be to set controller one to a Flex schedule with Monday, Wednesday and Friday allowed for watering and the set controller two to a Flex schedule with Tuesday, Thursday and Saturday allowed for watering. That way there shouldn’t ever be two zones running at the same time.