Neo is based on top of ES8 and uses the latest ES features as long as they can run directly inside the browser. This is one of the major design goals: the dev mode can run inside a browser without needing any JS related builds or transpilations. Instead of using any kind of templates, persistent JSON structures are in place. The combinations of these concepts lead to a pretty amazing performance and adds new possibilities for scaling to the UI area.
I haven’t seen any benchmarks or examples where using Neo produces extreme performance, but conceptually it makes sense that moving computationally expensive things to background threads would keep your UI thread snappy.