Yeah I've been looking at this recently. I like autowire's ability to create typesafe APIs shared across the client and server. Very promising, but not simple to set up...

http://www.lihaoyi.com/hands-on-scala-js/#Autowire

You don't need Autowite for that. That's pretty much basic functionality of Scala.js.

Really? From reading that guide I thought that Autowire made it easier by automatically doing the serialisation/deserialisation. How does stock scala.js do that?

Extra downside is code bloat. Scala.js on its own just maybe but combined with another major framework - forget it.

The amount of code bloat is offset by optimizing a medium-sized picture.