Yeah, Ruby claims to be Perl6 but when I tried it, it wasn't there in performance nor stability. The modules/extensions you want are there, but always somewhat incomplete.
I dislike Python's whitespace, but it is so far better in quality and completeness, compared to Ruby. Compare and contrast things like subprocess.Popen(). Python has all the variants, quirks and options you need in real life; just like Perl5 has.
I have not revisited Ruby in depth for a while now. I keep hearing of performance, scalability and stability issues with various Ruby-based tools (Puppet, RoR) so it's hard for me to find clear examples that Ruby has matured into the kind of rock-solid engines Perl5 or Python 2.x are.
Such maturity is truly useful... and dead boring. It's more fun for developers to keep finding new cool things to experiment with, instead of delivering something the world can rely on.