No doubt about that. The more time you invest in it the more amazing the results. I've found that it has actually gone beyond just the scheduling aspect. I find myself taking control of my landscaping in general, caring more about the vegetation I have, what it really needs, and how to best deliver it.
I have my home pretty automated, and I must say I really dislike WiFi. I went into my attic one year and routed Cat5 (for wired ethernet) to my home theater, kitchen and master bedroom so I could relieve myself of the majority of WiFi issues that I'd have otherwise. For lights, sensors, pool pump and water heater scheduling, I use z-wave. It's quite a bit more reliable and lower power, but wouldn't work for products like Rachio or Nest that demand a much higher amount of data throughput. Fortunately those WiFi repeaters aren't too expensive and are fairly easy to set up. Hopefully your client finds success with it.