Just installed the Ecobee4 and tossed my Nest. Installation was easy - thermostats usually are. I bought the myEcobee Bundle and installed it - very easy to install. Configuration is very similar to ScheduleTstatZones app - but many more capabilities with Ecobee than there were with Nest.
I have to say, the app has a LOT of things that can be configured - well worth adding a support package and letting Yves tailor the configuration to meet my needs.
Love having a solution that integrates ST with Keen vents and my thermostat. Overall our house stays much closer to our desired temperature in heat or cool modes.