I have two things I can add to all of the great post about this. We have the Echo.
The voice activation is the best I have encountered of all the devices I've tried equipped with it. Alexa knows every word. My iPhone gives me fits and I speak in the same voice with the same Hillbilly accent to both. My hands free in the car --forget about it.
Alexa is worth every cent just for the shopping list. We tell it to add something to the list, it goes to both phones. My wife and I both have the App on our phones. One of us buys something on the list, we check the box and it disappears on both phone's shopping list.
We are almost ready to tell it to start buying stuff for us:E