Developer Tim Fox, who works for VMware, explains in an interview with InfoQ: “Vert.x actually uses Netty. But vert.x is a complete platform for writing asychronous applications. Vert.x also provides a component model, file IO, and various other things you won’t find in Netty. I’d say, in the JVM space Vert.x competes more with, say, something like Akka (akka also uses Netty), i.e. it’s a complete framework.”
Fox claims to have conducted a few basic benchmarks and found that Vert.x outperforms Node.js, but his benchmarks aren’t ready for publication.
Fox says that Vert.x is already working on Heroku and OpenShift and will hopefully be working on Cloud Foundry soon.