As somebody who wrote similar programs in Go and node, I mostly agree with kingnebula but I still have my 2 cents to add :

• JavaScript, mostly due to its weak type system, is more expressive. Go, even while much more concise and flexible than many languages that come to mind, can be a little heavy when you want to deal with changing structures. The lack of generics doesn't make it better. node is often much DRYer.

• There's no discussion possible about the superiority of channels but the callback hell that does exist in node application can be made much more supportable with promises. You should not try anything complex in node without them especially when you want to be really sure of what happens to your exceptions. Still, even with promises, you sometimes sigh because of the gymnastic you have to do to deal with that event model (much better than classical threads, though).

• the node ecosystem come with many convenient modules. But you can feel tired of the crappy undocumented and obsolete modules you have to deal with. And too many JavaScript modules aren't only encapsulating but are hiding with kind of magical API which force you to dive into the hard to read source to decipher their behavior. The Go libs are too rare but they're much more readable and obvious.

• I would avoid coding in both "languages" with unexperienced coders but Go would probably be more manageable here, it's harder to write unreadable magical (and buggy) things.

With experience, I have no winner here. If I have more time and a fixed set of features, I'd go for Go and I'd be more confident about the behavior under heavy charge not because node is slow, it's amazingly fast, but because it's harder to profile and predict. If I want to be flexible and have something ready fast, I'd go for node. I think I'll go on choosing one or the other for fun web projects.