"Inferno is considerably faster than React," says the project's web page. "This doesn't apply to only benchmarks, but real-world applications that companies have converted to Inferno from React." The library also is only 9KB, which means it parses faster, particularly on mobile devices.
Inferno has a React-compatible API and can use React tools extensions for Chrome and Firefox. It has a partially synthetic event system, opting to only delegate certain events, such as onClick.
The goal with Inferno is to provide all the benefits of React, plus other features for people already familiar with the React ecosystem, including lifecycle events on functional components, server-side render streams, better real-world performance, lower memory consumption, and faster parse/load times, according to the project's GitHub repo. "Furthermore, Inferno allows people to switch their existing React projects to Inferno in a few lines of code using inferno-compat."