I realize you're probably joking (at least, I hope so) but just to talk to the scalability point, I've had much better success scaling Netty (which Vert.x is built on) than Node. I've been able to scale Netty to more concurrent connections and Netty performs much better under load than Node. Just my experience.
If you read the docs we specifically mention the "Fibonacci" farce.
Vert.x (unlike node) does not force you to do everything on the event loop. It has a hybrid model.
For things like long running calculations (e.g. Fibonacci) or calling blocking APIs, we support running them on a background thread pool so you don't end up doing stupid things on an event loop which are not appropriate for it.