1. I have used both in production. I have been using Node.js for about 3 years now (I was a very early adopter. "JAVASCRIPT ALL THE THINGS!!!").
2. I have also been using Go for about a year now. I can tell you first hand, if you go with Go (see what I did there?), you will save yourself MASSIVE amounts of headache.
3. Javascript is very fast. Yes this is true, V8 is very fast... however, only if you are benchmarking a simple benchmark. As soon as you start adding in complex application logic all that performance goes out the door because the virtual machine has a very difficult time correctly inferring the type and thus not being able to optimize. But if your application consists of a tight loop, it will be fast.. so its got that going for it :D
4. Node.js: Callback hell. Must I say more? With Go, you can have each connection use a different Goroutine and use "blocking" IO AND still have better performance than Node.js. Why? because you aren't really blocking, while some IO operation is being performed on that goroutine, the scheduler does work on other goroutines/connections. So you get all the benefits of non-blocking IO without callback hells. There is absolutely NO REASON to have callback spaghetti when you can simply let the runtime take care of the nauseating details.
5. In my 3 years of full time node.js development, I have honestly only had ONE occasion where I used the same 4 lines of code both in the server and in the client. I shit you not. There is no merit to the claim that you use the same code on the server and on the client. SURE... if you were writing a simple game and you wanted to replicate the game logic on the server to make sure nobody is cheating... it might be useful. But really ask yourself if you want to perform complex logic on the same thread that everybody else that is trying to reach the server is waiting on. No, you don't.
6. Ohh and did I mention Node.js isn't really all JavaScript? A good portion of the pakcages on NPM are also written in Coffeescript. Hope you don't mind learning another language to deal with a package you depend on. So much for using the same language for both server and client!
7. With Go you get type safety. This CANNOT be overstated.. except to maybe ruby-ists(jk jk! don't shoot me). Also, you get a unified tool-chain for pretty much everything you need from formating to getting modules.
8. The one benefit you have with Node.js over Go is the massive number of packages available on NPM. But most of them are useless abandoned junk. So, even that is questionable.
9. Testing: Lets just say that in Node.js/Javascript you would have to write tests that check the type of a variable. tsk tsk tsk... This is the only way to properly test JS and make sure nothing crazy is going on. OR!!!! here is a revolutionary idea!! let the damn compiler do it for you! MIND BLOWN!!!
10. Anyway that is my two cents. I hope I didn't come across as a Node.js hater.. but having dealt with its warts and limitations for the past 3 years, I would only wish it on my worst enemy.
11. Good luck