I'm not sure about RubyMotion, but I can speak to Titanium as we use it to build our TripLingo language learning apps.
Appcelerator Titanium does not compile down to anything - rather it bridges a JavaScript runtime to the native layer: either iOS or Android. It's not as fast as coding in ObjC or Android Java, but we see performance which is very close to that of native and have the entire underlying native SDK available for use.
These frameworks typically just allow you to wrap native methods with JavaScript... so you're not really writing to a single cross-platform code base. Morever, if you can build your app entirely in the HTML/JS/CSS side of things, you're golden... as soon as you start to bridge between the Native and JS layers, things get messy (and often very slow).
What? You make no sense. In your original article you advocate going native for now and eschewing Web tech. Now you say that "you're golden" if you use Web tech? Then you top it off by saying bridging down to native is slow.....
Are you just talking out of your ass? Have you actually built an application using Ansca Corona, Ruby Motion, or Appcelerator Titanium? Have you built a published native and Phonegap app to the Android or iOS store? Well, I have done all of these - and I even speak about it at conferences[1][2]. I can safely say you have no idea what you're talking about or you are pushing a hidden agenda.
Could you please either link to a copy of your talk, or some material? Or alternatively (if possible), just give the 3 sentence version of your talk? I'm just about to decide what to system to build a new project on, and I'm interested in your opinion.
