As a developer that considers himself more on the UI side of things I really enjoy sdks that make things easy and fast. Examples that I have used in the past when programing Flash are tools like Fuse, Tweener, TweenMax and APE.
I am excited to finally start getting into mobile development. I signed up to use the Corona SDK and I have yet to code anything that is ready for the app store. I am just futsing around with the API’s right now but I am really excited to see that the Corona SDK team are making things like physics and animation really simple for the developers.