We've started building Bugfender using GORM and it was good for the initial job, but we now decided to remove it completely and continue on a lower level.
We've summarized our whole experience with Go here: https://bugfender.com/one-year-using-go and we're just wrapping up another blog post with the Go pros and cons (from our point of view), which should be out soon as well.
The biggest problem with go is, that it is still a very fast and changing ecosystem. Which is great for a new language, but didn't serve us too well for building something stable.