I was actually pretty impressed w/ the django book, even in its unfinished state. I also "get" django more than I get rails, so I'm definitely attracted to it (after quick looks at both).
My point was just that there's so much behind rails right now that it sure seems like any issues with it scaling will get worked out more quickly than they might with other frameworks. There's also already an ecosystem of 3rd party apps around it.
Also see our docs, at http://www.djangoproject.com/documentation/ .
Disclaimer: I'm a Django developer and coauthor of the book.