I've been using this engine, it's quite nice, and targets all the platforms one might be interested in. It only took a few hours to figure out how to translate some code from love2d.
I have become a huge MOAI fan. I've built a physics game, a generalized data/entry application, a board game, and a few other things (internal projects) and I can't say I ever want to look at Objective-C/Android SDK's again. After deploying my apps on all platforms, I see absolutely no point to fall into the developer-brainshare trap again.