Got my Echo Auto and I'm rather underwhelmed. I have not yet put effort into finding "the right place" to mount it.
Near as I can tell it's just a microphone to talk to the Alexa app on a phone. The Echo Auto device does not connect to the car directly. It connects (via Bluetooth, I think) to the phone. Then the phone connects to the car's radio. The detection/pairing process was smooth, just your typical 'Alexa add device' process using the app.
The mic pickup is uneven, at best. I'm thinking it needs to be clipped to the overhead visor and not down on the dash or console.
But what's annoying is it clips audio. If you ask it the weather forecast or the time while a bluetooth music source is playing the spoken text gets clipped at the end. It's not letting the spoken result get finished before returning to the streaming audio. Which makes asking for the time tedious as instead of "The time is eleven fifteen AM" you get "The time is eleve-" and then back to whatever was playing.
I'm also unsure how well it handled initiating commands in the app when the app wasn't in the foreground. As in, playing a Pandora channel through the Alex app, and then using the Waze app for directions in the foreground. The music kept playing, and Waze continued to use the speaker on the PHONE, but the Echo Auto seemed to not be able to reliable get a connection going. That is, speaking "Alexa, what's the time" did light up the blue mic speaker on the Echo Auto. But then nothing seemed to be happening on the phone. I'm betting this has everything to do with how the app is being managed on the phone (sleep modes, etc) so that might be a factor. This was with a Samsung S8, so ymmv with other phones.
So that's my first test. Plug it in, easily pair it, use the app to play some music (from a Pandora 'station') and then tried some typical Alexa commands we use at home. I'm underwhelmed. I didn't expect "a lot" but I did at least expect the same rapid handling of commands that I get from the home devices. That was not the case.