As far as serverless Go is concerned my experience has been only with Heroku as I prefer hosting on my own instances and Heroku seems to be reasonable for my use case. I hear fly.io is better in terms of performance and they do offer distributed PostgreSQL.
I guess those who are already into AWS would probably be choosing Lambda for serverless Go. If the experience is same as Node JS or Python on Lambda, Then I don't think there would be much to complain other than the cost; But of course cannot match the speed or cost of a CF worker for the reasons you've pointed.