[colinta]

I think the gains are huge, but it depends on your preferred workflow. I know some traditional Xcode developers who kick and scream at the idea of loosing their IDE, whereas I prefer to live in the terminal.

Workflow is one thing, but then writing Ruby code is so fluid. Notice that there's not a lot of preamble (imports and such) that you need to take care of in the Ruby code, I think that's great. But, again, language and workflow are very personal, and I think every tends to "think they're right" ;-)

[octopus]

Agreed, RubyMotion is appealing if you prefer a fast development cycle. I tend to use C++ for most of my programming projects but every time I've used a more "dynamic" language (Python or JavaScript in my case) I was amazed at how fast I can try/drop/improve on an idea and see the code running. The only problem I had with the "dynamic" languages was the speed of the resulting code, RubyMotion seems to be in the sweet spot between a statically typed language and a dynamic (usually interpreted) language.