One of our main priorities when we first started out was to build something stupidly quick. We hate loading screens as much as the next guy, and since we've really prioritized mobile we intend on building a solution that still works great on a small screen with limited resources.
Here's a comparison of our hand-rolled rendering engine (templates.js) vs another prominent player in this space (Ember.js):
We've also seen about 10x better performance vs. handlebars as well (benchmarks available in the repo). All of this really adds up when you're rendering on your mobile device. Speed is everything and when you're on mobile you want the smoothest experience possible. We intend on keeping it up and trying to improve as much as we can when it comes to this aspect.
Just wanted to improve awareness of our rendering engine, and I hope to hear more feedback about what we have, what improvements can be made, etc. Thanks
Look at the NodeBB Templating Documentation for the basics or the templates.js repo for more advanced use cases.