Same experience with phonegap + sencha touch. My personnal conclusion is that :
if you're doing "business" app (aka : where data matters much more than UI responsiveness) AND you want to release the app both for Android and iOS : go Phonegap.
Otherwise, and until the majority of smartphone become as powerful as the iphone4S, stay native. With ARC, developping on iOS with Obj C has become pretty much like developping with any other language (if not better).