Work-in-progress benchmarks.
$ ./measure.py react-a.min.js >a.txt
$ ./measure.py react-b.min.js >b.txt
$ ./analyze.py a.txt b.txt
One thing you can do with them is benchmark initial render time for a realistic hierarchy:
$ which jsc
/System/Library/Frameworks/JavaScriptCore.framework/Versions/Current/Resources/jsc
$ jsc react-0.14.0.min.js bench-pe-es5.js -e 'var START=Date.now(); React.renderToString(React.createElement(Benchmark)); var END=Date.now(); print(END-START);'
45
Substitute js or v8 for jsc to use SpiderMonkey or V8, respectively, if you've installed them.
To create one, copy extract-component.js to your clipboard and paste it into the Chrome console on facebook.com, perhaps after changing the root ID if you don't want the tree with ID .0.
Then to convert it to ES5:
babel --whitelist react,react.displayName --compact false bench-pe.js >bench-pe-es5.js