"I don't know much about Spring, but In Vert.x 1.x each Verticle that is deployed has its own classloader, so it's hard to share a context across verticles." -- Tim Fox (Vertx creator)
"A vert.x instance guarantees that a particular verticle instance is always executed by the exact same thread. This gives you a huge advantage as a developer, since you can program all your code as single threaded. Well, that won't be a big deal to you if you are coming from JavaScript where everything is single threaded, but if you're used to multi-threaded programming in Java, Scala, or even Ruby, this may come as a huge relief" -- lol
"A vert.x instance guarantees that a particular verticle instance is always executed by the exact same thread. This gives you a huge advantage as a developer, since you can program all your code as single threaded. Well, that won't be a big deal to you if you are coming from JavaScript where everything is single threaded, but if you're used to multi-threaded programming in Java, Scala, or even Ruby, this may come as a huge relief" -- lol
http://www.youtube.com/watch?v=bzkRVzciAZg