I would also like to voice my opinion on the matter.
I've had my Racho unit running for about a month now, and it still says "0 gallons saved" in my stats. Given the amount of downpour we've had, there should have been a significant number here by now.
I know the unit has skipped watering schedules due to rain, so I know it works; which means that the Rachio team still haven't figured out how to account for the water saved when on a flex schedule.
While the math and variables might be trick, I consider it a flaw/bug, given that an unrestricted flex schedule should be the optimal setting and primary use for the Rachio, giving the best savings possible. That should be noted somewhere, and not with a big '0'.
Consider a "flex" schedule where there's no rain detection, no sun/cloud/shade/evaporation coefficient detection, ever. Call it "static seasonal".
This should give the "best fit" watering schedule for the type of lawn, shrubs, flowers, which is periodic and doesn't change, except for seasonal adjustments, which is basically what all "dumb" units support.
Now measure this "static seasonal" schedule up against the active flex schedule, but with all sensing turned on. That's your full water savings 100%.
An advanced feature would be to also support rain sensors, which a field to alter how long a rain sensor would disable the "static seasonal" program from turning on based on actual precipitation. Alas, how long it would take for the cork to dry out and allow a "dumb" unit to start watering again.
A super-advanced feature would be to allow someone to enter their previous "dumb" unit schedule (still allowing for seasonal adjustment), and measure against that. It wouldn't handle people who where constantly changing their "dumb" units, but really, their additional savings would probably be minimal, and I'd say that's a 1%, not worth supporting.
Comments? Other ideas?
I just don't want to see a "0 gallons saved", when I'm using the system with the most optimal settings!