WKWebView for Hybrid Apps in iOS 8

With the release of iOS 8, Apple has brought so many changes in the Framework existing classes and have introduced new classes.

For Hybrid App development we introduced UIWebView, Which is used for displaying the Web content. 

However, with the release of iOS Apple has introduced a new class called WKWebView. which is derived from UIView here is the inheritance chain for WKWebView.

NSObject
|
UIResponder
|
UIView
|
WKWebView

WKWebView is also derived from UIView similar to UIWebView, So what are the difference in both.

Performance