I have worked with Titanium extensively and I'd say if you do it right, you have a LOT more than only 50% re-useable code -- probably closer to 80-90% that work

I have worked with Titanium extensively and I'd say if you do it right, you have a LOT more than only 50% re-useable code -- probably closer to 80-90% that works perfectly cross-platform. Of course it depends a lot on what UI elements the project requires, so I imagine the range is quite large, but 50% still seems really low.