To preface; I'm an experienced web developer, though I have barely used nodejs, and have not yet had the opportunity to work with emberjs (though I've done a decent amount of work with backbone).
I'm about to start a project to build a web based writing application (literature). In theory, the user would potentially have the application open for long periods of time, perhaps leaving it on. I intend to develop an expanding functionality set over time, which I would like to be able to drop into different places with relative ease. For example, perhaps develop a character list which I could then include in many places. I'm keen on using emberjs for the experimentation alone, but it also sounds like a good client side framework for the job.
I've looked at django briefly (haven't used it much before), but given that I'd like to use emberjs, it seems like django isn't a great choice as I'd be opting not to use many of its most compelling features.
Would writing my server side code in nodejs + express be a reasonable choice? The web application itself will have common features like login, admin, different permissions for users/tasks (eventually) - but I also anticipate some more beefy stuff.
This is a solution that works well for my team and I so far. While lacking express, Charcoal is a good starter project to get up and running with Ember without a Rails asset pipeline and Express can easily be added as middleware. In addition to using Express to serve your JSON, it can handle the minimal HTML needed for such requirements that Ember can't fulfill by itself such as SEO since content negotiation capability is very simple in Express.