Corona SDK let me go from no real coding experience in the past 10 years to making a convincing prototype iOS game within a month. But to make it App Store ready (content and polish) has taken several more months and I'm still not there. I sure would like to earn at least $1 in October though.
I get frustrated over Corona's limitations such as no way to add GameCenter support without adding OpenFeint (which more than doubles my app's file size and bloats it past the 20MB 3G download limit).
With Monkey, when you build, it actually creates the native code for you right on your own computer, so if you want to add Game Center, or something to that affect, you could actually open the code in XCode and do what you need to do, no limitations - which is why I've become a fan actually.
I can open the code in Eclipse and add AdMob ads if I want to after I've created the game in Monkey.
The cool thing about Corona is how popular it's becoming, and how they are developing new features at lightning speed. As a subscriber, the daily builds are really impressive.
I get frustrated over Corona's limitations such as no way to add GameCenter support without adding OpenFeint (which more than doubles my app's file size and bloats it past the 20MB 3G download limit).