Sencha Touch is a HTML5 mobile application framework. Built for enabling world-class user experiences, Sencha Touch is a framework that enables developers to build fast and efficient apps that work on iOS, Android, BlackBerry, Kindle Fire, and more.
We see more and more companies using Sencha especially to develop quick prototypes and launching the apps on all platforms at once. One basic advantage is that Sencha cuts the development costs, because you need not invest on technology for iOS and Android separately. If time to market is of the essence, then Sencha may be a good option. But the performance cannot be compared with the native apps–Sencha apps do not have the coolness factor and responsiveness that a native app can give. However, it is still a great option depending on what your apps need to do.
Know more about Sencha framework here.