Is this right? Java really has better latency than Go right now? And with 2 processors, Go's latency is 25ms for 50 concurrent requests. Anybody with better experience care to comment on this?
You just have to know where to look for, plus you don't need to throw away mature languages and tooling.
2 - Go's CPM paradigm is not necessarily more performant than the preemptive threading model of Java, and I don't believe that has ever been claimed for CPM. It is claimed that it is "easier" to write concurrent code using the (CPM/Go) message passing paradigm, but in my experience, you either get concurrency (and can do both variants ok) or you don't, in which case any real world concurrent system will hardly be "easy". That said, for the concurrency novice, Go is far less intimidating experience given the language level support for goroutines (fibers), channels, selectors, etc. (think Java NIO ...)
Go is getting a lot faster and pretty quickly.