Focus on speed and modularity next to the clear code sounds interesting, but supporting IE 9+ only is kind of a bummer here, because it means "no" for XP users (I use XP64 on my desktop for instance) and there is still substantial number of them.

(And I do curse Microsoft for making IE 9 Vista+ only browser, which is quite likely explainable by use of some shiny new undocumented API, that wasn't available in XP and before. Microsoft and their browser tightly coupled with OS...)