@Quincy Well, Rachio Iro allows 4 scheduling options that trade off simplicity vs. optimum operation. For the ‘smarter’ schedules, take a look at Flex Monthly and Flex Daily. The 1st article here should answer your question, and the other 2 add some implementation options. The concept implemented is, as far as I can tell, quite standard for the agricultural industry and the associated irrigation specialty that applies. There’s a lot of published research papers from government and universities out there that’s behind all of it.
Note that the system currently does not use a soil moisture sensor, but rather predicts MAD levels based on your precipitation, irrigation, soil type, root depth, crop type, etc.
As far as shopping around, be sure to take a look at the forums for all of the controllers that you’re looking at. You found this one so it sounds like you’re already going down that route. Anyway, it was striking to me to see the difference in how active the community is here vs. others. The customer support is hands-down the best I’ve ever experienced. Let us users know if we can help you in any other way.