Had an existing project that I wanted to shift to Koa.js but I had some npm modules which had gyp bindings and because they hadn't been updated to work with node 0.11, I stuck with express. I did make the gyp bindings work but then I had to start maintaining the module on my own for the project and deployments, so in the end it was not worth the hassle for me.
I think I will rather buy some books, read some blogs and write my own web app instead of paying $199 for a certification, actually I am already doing that.