This is a great write up. We have a very similar stack for a separate team based project we're working on. The only difference is the front end stack, and we have tornado sitting back on the backend to serve http requests when needed. What's the benefit of Mustache/Backbone over just writing your own client side templating, in a practical sense? Last time I used a KVO framework, there was a performance penalty that I did not like. Does Backbone have any performance issues? Or even mustache? What's the trade off of having these frameworks versus generating custom tempting code?