Ian Bicking (a python developer I have a great deal of respect for) has a good comparison of Python and Ruby, focusing on the things that are unique to dynamic languages.
It’s interesting that both frameworks were extracted from large development projects in roughly the same time period, although Rails has been publicly available for longer, and has more mindshare at the moment.
I’m happy with Rails, but I wonder whether I would have bothered with it if Django had been available when I started looking at Rails. The thing that kept me away from Rails for a long time was that I didn’t know Ruby. I was (and still am) well-versed in Python. I still prefer the cleaner syntax of Python over Ruby, although the latter does have some features that I find compelling.
I wonder about the impact of one aspect of Django though: the fact that the model generates your databas schema, instead of the developer generating the model from the schema (which is the Rails model). I suspect most DBA’s would go into convulsions at the very thought of this. I can certainly see how it would ease moving from database to database.