My only experience with Go was to help advise a team when porting a Java cache. They struggled with performance because Go kept fighting them. This was partially due to it having a poor concurrency library, resulting in excessive use of read/write locks whereas Java's advanced capabilities made more things lock-free. The database founder noted that Golang is slow single-threaded but makes up for it via concurrency and low latency.

To my unexperienced eyes, it seemed like a real PITA mostly because the Go authors insisted on artificial limitations externally, but bypassed them internally. I certainly have not found it hard to make Java fast and the core developers have always been open minded when I've talked to them.