We'll talk about this Tuesday :) People usually have a very good reason to prefer the language they're more comfortable with, because it makes them more productive. Of course, it could be easy to dispell if some guy insists on writing only assembly, or C++, vs Python. I've known a guy who wrote whole Windows GUIs in assembly, it's pure madness.

There are many valid technical reasons to rather choose C than Python, Java than Perl, or PHP than Go, Erlang rather than C++ ...

But Perl vs Python vs Ruby? Hardly any difference, extremely similar dynamic languages. It's only a matter of personal taste at this point.