Why is Ruby better than Python managing language? (is it?)

Hi there, I'm starting to develop an application that is very demanding in semantic capabilities, lots of relations between concepts... I heard that ruby was better than any other programming language to manage language... Is that true? Why? (I still have to choose the language and Python with Django is the other option I have, at least for the prototype. I won't be the main programmer, but I have to start developing the idea...)

Thanks to all,