Well, for me, it's readability and maintainability. I find Ruby unreadable, and if I want to hire a programmer, it's easier to take a Perl, PHP, or even C# developer and teach them Python than it is to teach them Ruby, at least from my experence.

I don't think there's anything wrong with Ruby as a language, and until it was added to most languages, the scaffolding held me in awe...

I just prefer Python's readability.