Is ReactJS really fast?

The tl;dr I get from this is that angular docs don't do a good job of actually documenting "fast by default" options.

I don't use React for it's speed, I'm sure I can make anything using vanilla or ember, or whatever just as fast. It's the way it makes you think about things...the developers on my team are now much more productive. They can jump onto something another developer has been working on and see what each component is doing. It's the declarative nature of React and the way it makes developers think about how they compose their components that makes it a great framework. And let's not forget the reason behind a framework...for developer efficiency. There are no frameworks that are the panacea to everything either, which is probably why the framework arguments break out every single day in the JS world...people think the framework they choose is the one true solution, when in fact, there are many ways to build a building.

> Or the strange lack of any demonstrable examples of the performance improvements achieved by this feature... except the comparison demos.

React is winning because of real-world experience. Blog posts are somewhat meaningless, arguing specific nuances back and forth. Who knows what's actually right. But when you actually sit down and learn React, and use it in a complex app, you understand how easily it lets you fine-tune performance, and instead of getting in the way it helps you along the path to blazingly fast UIs.

Nothing is magical out of the box, the key is to help the user along the way and that's exactly what React excels at. Performance is a definite factor for choosing React.

Software doesn't achieve the level of fame of React (or Ember, or Angular for that matter) solely by hype. It may have a brief period of fame, but several years long of building a passionate community means there probably is something there.

This is a great point, ReactJS has many benifits. People should choose it based on those merits not "speed".