I thought Alexa will win. I haven't tried Amazon Echo yet but with this review and comparison, it makes me wanna get one next time.
Amazon Alexa wins for it's devices and ease of deployment. Google is coming from an assumption that Alexa is somehow it's lesser rival, when it is actually superior in the ways it needs to be. Amazon's approach is more open than Google, whose approach seems to be more like Apple's walled garden. The Google Home has the power of Google behind it, but so does Alexa. Google Home devices are not as capable as assistants as Alexa is. I had both of them, and I had started out with a Google Home, then two. The Alexa Echo Dot with it's external speaker jack and highly visible light ring are more useful. There are more devices which integrate with Alexa.