After 3 years of research and testing (and 2 home brew test systems, 1 Ardrino, one RaspberryPI that both 'worked') I decided to install what seemed to be the winner - Rachio V2
I installed 4x 16 station and 1x 8 station V2 controllers in mid summer of 2016. Have 2 more 8 station controllers to install soon. Love the system. My brain hurts from the intense pain of dealing with 5 controllers now (72 stations and growing...) as not only do we have water rationing here, but everything has to come off my 2500 gallon storage tank/boost pump that I cannot run dry and that requires a constant dance with overlapping schedules of 5 (7) controllers.
My very first PM to Rachio (Franz) within a week of install was begging to link them soon... at least in my lifetime.
It is without a doubt the biggest shortcoming of the system in my eyes and given how good the rest of the system works, it's a vital, needed fix.
While I am whining, WiFi 2.4... 802.11... It a new era (to few channels, too much overlap). next generation hardware minimum 802.11ac...
Need better ways to get more soil moisture sensors in to the system - currently I get the data from 5 sensors on the property (BTE to 802.11ac/POE) upload it to the cloud and then hand manage the watering to Rachio since I have not worked out how to get into the API to send data to specific stations.
I do believe the feature set of Rachio is right up there with the best and I do have faith they will find a way to deliver this vital feature.
Early on in this tread there was a comment along the lines of not that many users have more than 1 (or perhaps 2 controllers)>
I suspect this is rapidly becoming untrue, and as someone said - with mandatory rationing the number of stations will just keep going up to manage the watering needs of anything more than a condo.
Still, Rachio is one of the very best solutions out there on a cost and feature basis, but you're not the phone company, you cannot accept 'good enough'
I'll get back in my box now