Seeing these numbers (although as the author states, the data needs to be taken with a grain of salt since he didn't try to set up a more "proper" test environment) really makes me want to take a serious look at vert.x, but what you mention here is my main concern.

Node is a joy to use because of the NPM, and all the available libraries. I'd hate to lose that.

That said, so long as it has a solid websocket api, and I can do routing in it like I would express, I'd give this framework a shot