Pick your Horse
This article is great example of the complicated landscape a developer today must deal with. I researched both node.js and ember.js just now, being a current user of Sencha Extjs.
Very little difference at the front end, AJAX calls with callback so they are asynchronous. What's different is they target backend of servers which have no integrated web serving. and to a smaller degree, no integrated database and server side languages.
With the current focus on doing things on the cheap and, many times, facing comsumers on web, businesses are using open source servers, cheap hardware and open source databases and licenses. Those environments have no way to natively develop anything. So yeah, this is good stuff if you think that's where your job will be. But those environments also have a ton of other frameworks and languages targeting them. If you can pick the winners and losers from that mess, take your talents to Vegas and forget software as a career.