I’m joining the Go team at Google 10 years ago
It is not excellent. All other editors I used autoformat Go code after save. There are two types of format provided by IDEA - IDE Format & go fmt. Both not ideal. IDE Format does not format code according go guidelines. It can delete unused imports if you go through options. go fmt does not delete unused imports, and as result code is not compileble.
Refactorings are missing in IDEA. It is not excellent, it is something you can work with.