I received a new Gen 3 controller this afternoon, to replace a Gen 2 (it was NOT a Rachio issue!), and wanted to thank the Rachio support team that worked with me to get it done. They were extremely helpful and flexible. As I said in my review on Google, this is what customer service is supposed to look like!
It took me about 30 minutes to remove the old controller and pack it up, install the new one, get it on the internet using my 5G wireless, and setup the schedule. It also included cleaning up my wiring a bit (I MAY be a little compulsive!). My point is, Rachio has the start up process figured out, and it works well.