I've used Python for about about eight years, and Ruby for right at six months. It took me about a week to feel competent in Ruby, and about a month before I was really comfortable with all of the metaprogramming functionality. Add another month to that before I really grokked ActiveRecord.

I much prefer Python. I thought for a long time that this was because I learned most of the fundamentals of computer science and professional development in the language, but I'm at the point now where I'm sure that's not the case. The Zen of Python really shows the differences between the two of them - "explicit is better than implicit", versus Ruby's "convention over configuration". I don't mind writing some boilerplate in Python, because the boilerplate is itself fairly terse and fully informs you of your system's architecture in the process.

I hate that functions aren't first-class objects in Ruby. Hate it. The subtle distinctions and behavioral differences between blocks, Procs, and lambdas are infuriating.

There are many things I would change about Ruby, but there's nothing wrong with it. It's just not a good fit for my way of thinking.

All that said, the question was "Has Python killed Ruby?" No, it hasn't. Ruby is still popular, and I think it very much fits the manner of thinking of many developers. For them, thinking in Ruby is natural and wrangling Python into submission would feel like writing Ruby does to me.