Very interesting feedback. I'm a Go newbie and the goroutine/channel duality sounds delightful from where I stand, but once again I have no professional experience with Go yet, only sample programs to get used to the language.

One question though: your advice is to write things serially first before moving to concurrency, which for me is general programming common sense, but would you argue that once you start writing concurrent code then channels are not well suited compared to "good old" sync primitives (mutexes, etc.)?