This is going to sound unfair, and maybe it is, but here goes: The biggest difference between Ember and Knockout is that Knockout has excellent documentation a

This is going to sound unfair, and maybe it is, but here goes: The biggest difference between Ember and Knockout is that Knockout has excellent documentation and tutorials, and is very easy to pick up. The tooling and knowledge needed to get a basic proof of concept app up and running from scratch is trivial with Knockout. It fits into whatever toolchain or build process you already have; as a result it's easy to add Knockout to an existing Django or Node project. By contrast, Ember has poor documentation and tutorials. This was especially bad at launch, but even today it's very limited, and significant chunks still refer to Sproutcore. Some of that documentation is apparently still relevant, refers to the Sproutcore v2 project, and just haven't been updated with the new name. Other bits are apparently referring to the Sproutcore v1 project, and aren't relevant. Good luck figuring out which ones are which. Ember also has very idiosyncratic ideas about how projects should be built; again this isn't really documented. It's hard to build an Ember app from scratch, and it probably will not work with your current build process. It feels, in some difficult to define fashion, more like what I'd expect from the Java ecosystem. I'm not a fan. As I said, I'm sure that sound unfair, and it may well be. Ember fans will no doubt be able to explain that it's much easier than that, that my problems were all my own fault, that the documentation is already much improved, and that any quirks that do exist do so for very good historical reasons. And they're probably right! But I came at Ember cold a month or two ago, tried very hard to figure it out, and bounced. As a result, I have no idea how Ember really compares to Knockout, because I figured out how to write my app in Knockout, but I couldn't figure out how to write it in Ember despite a very concerted effort. Take that for what it's worth. :) (My impression, incidentally, is that Knockout is sort of what the Ember project wants to be, but they're still struggling to strip out the cruft they inherited from Sproutcore. Both projects have a focus on magical "it just works" dynamic bindings, which means you have incredible awesome power but have to be a little careful not to blow your leg off via some behind-the-scenes magic you didn't even realize existed. Backbone, on the other hand, is a very barebones framework; it's almost more like a toolkit you can use to build your own MVC framework. That's valuable too, depending on your needs.)