Snakes and rubies
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You don't have to agree with him 100% to see that there are some tasks that Python is better at. Ruby is a great lanugage, but it has faults (like all languages). Matz's Ruby Interpreter is slow, much slower even than other scripting languages. Weak-to-nonexistent Unicode support. And not as many libraries as Python or Java.
Related: I'm interested in checking out Python's SQLAlchemy -- it sounds pretty sweet.