I think this speaks volumes about the power of HTML5 vs native app development. What I find interesting is that both Apple and Google claim to really push HTML5 yet they still make sure their native apps run significantly better – for now at least because I am sure their futures OSs will offer better support. I am surprised a company like facebook even attempted HTML5 vs a native app to begin with and am surprised it held up so well to this point. This shows HTML5 does have power but not enough compared to Xcode. Xcode offers a lot more and HTML5 is really only designed for simple apps. When you are a company like facebook that has millions of users I could only imagine how bogged the app could easily get. Well here is the article for your reading pleasure:
Article: http://www.theverge.com/2012/8/23/3262782/facebook-for-ios-native-app
Another article: http://mashable.com/2012/08/23/facebook-ios-5/