Check out the Mithril example in the comments (http://jsfiddle.net/qQ59s/). I'm finding Mithril to be the most straight-forward, easiest to understand framework I've used. Note that Mithril does DOM diff'ing.
I may be biased since I wrote it and I’m using Vue.js everyday, but I think it is really comprehensive compared to others.
Edit: if you want to know more about Vue.js [2], especially how the data binding works (hint: no dirty checking, no ES6), the FAQ [3] is a good read.
IMHO, Vue is a very interesting project and I think this particular article is a very good fit to show its strengths, but I think my comment (at the bottom of the article) still applies to it. For example, it's not particularly obvious how to change a binding to use the blur or the change event, without scouring the documentation. Or that `v-model` and `computed` and `$get` and `$set` are the names of the things that, in conjunction, do what you want in this particular case.
In that sense, the Mithril code is more straightforward to write and to control, because the abstractions that it provides complement - rather than replace - a naive implementer's workflow. This is the aspect that I believe eddyystop is talking about.
In particular, I like that the JS code is free from cruft as in the other examples there. I also like that the HTML stands on its own which makes the UI design process easier.
Prior to this I had been considering RiotJS[1].
[1] https://muut.com/blog/technology/riotjs-the-1kb-mvp-framewor...