We have a nest and really like it. What I don't like is their refusal to add apple watch function to their app. A lot of people like the ecobee. If we didn't already have the nest, I'd buy the ecobee. I like that you can add sensors so it heats/cools based on the room(s) occupied. And they have apple watch support in their own, free app.
I did finally give in and buy a third party app so that I could control the Nest from my watch (and it has geofencing.) I had a knee-jerk reaction to buy an ecobee to "show Nest"... but then my brain kicked in and I realized that the only "showing" I'd be doing was what an idiot I was to spend $300+ to get a new thermostat when a $2.99 app took care of my issues! haha!
once the nest learns your routine (if you have one), it's pretty much hands off... comes on, goes off, goes to away, etc. it's nice to be able to control it pre-cool the house in the summer if it's not a routine function that Nest has learned.
Now when/if the Nest goes bad.... i'll seriously consider ecobee. it doesn't "learn" but you can set up programs.
we don't have a smart lock. we do in and out the garage door... so it's not necessary. I do plan to add the thingy to our garage door so that I can use the app to open/close it and it also monitors if it's open or not!