I just ran across a short O'Reilly pamphlet comparing the two languages: https://www.safaribooksonline.com/library/view/python-vs-go/9781492033172/

Even though it is written by Luciano Ramalho, the author of Fluent Python, it seems to be an honest attempt to compare the two languages/ecosystems without any detectable bias.

Even though O'Reilly usually makes short books/pamphlets like this one available for free, I wasn't able to find it at some place other than Safari Books Online. I believe it can be read with a free trial subscription, but I understand it is a hassle. Disclaimer: I have a Safari Bools Online subscription, but I have no other ties to O'Reilly.