Of all the open source projects that have impressed me over the years Vert.x comes close to the top - probably at the top if you catch me on a good day. It's relative simplicity belies a combinatorial complexity that allows developers to go from zero to enterprise ready in small steps or giant leaps. The fact it has been imitated in recent years in other languages is just another clear indication of the power of the project. And yes, it clearly takes a leaf or two from Node.js and others but as has been said before: "Good Artists Copy; Great Artists Steal."
I've mentioned a few times about reactive, asynchronous patterns and how they're appropriate for things such as microservices. Vert.x is already a great way of developing microservices from scratch but I also believe that the concepts of the polyglot, non-blocking, event bus is ideal for bridging and integrating with existing applications or services. There are going to be a variety of ways for creating (micro) services and applications, but I believe that Vert.x offers some building blocks they all need. I'm hoping to see us use it much more in the coming months.