We just switched from backbone to angular. The thing that sold me was data-binding. You could write your own with backbone but it's done so why bother. Also the code reduction was about 1/3.
You don't need to write your own data binding in backbone. Several smart developers have already written plugins for this very thing. I usually forget about backbone plugins when workin on a new problem, and get halfway down my thought process before remembering to check https://github.com/documentcloud/backbone/wiki/Extensions,-P.... To be fair, the backbone website does a terrible job of promoting these resources.