We chose Go because of its readability and focus on writing readable code. Performance also played a part in our decision, as did ease of deployment. It's also an easy language to learn coming from a PHP background which is what most of our existing developers have. Another benefit is that you'd don't need a sepearate web server running next to your applications since Go comes with a built in web server that's production ready out of the box. This is very useful for writing and exposing HTTP APIs.
The drawbacks of this decision are that not everyone at LS knows Go and so extra time needs to be spent ramping up on a new language. There are also a few bumps that come with this choice, as the programming paradigm is slightly different when coming from PHP. For example, since Go is a compiled language, sometimes you forget to compile it and wonder why your latest change isn't taking effect. The type system is also a bit of a change coming from the loose typing of PHP. The other challenge is that the Object Oriented nature of Go is different from PHP (Composition vs Inheritance). None of these drawbacks are deal-breakers however.