Should you use RubyMotion or Objective-C for iOS development? That depends…
If your team is currently building web apps, and they happen to be Ruby-focused, then RubyMotion will enable you to create a minimum viable product (MVP) using skills that you already have in-house. However, if your team is currently Objective-C focused, it may be easier for you to build your MVP in Objective-C.
Keep in mind that I am Ruby-biased, so I see advantages on the RubyMotion side of the question. Building the web and mobile pieces of an app in the same language means that expertise can be readily shared throughout the team. Shared expertise makes the team stronger.
Thanks again to MagicRuby and Aloha Ruby for asking me to speak, and to Confreaks for recording the talk.