The first and most important: community. (Oddly enough, as I write this there are 666 projects tagged as django. 'turbogears', 'tg2', 'tg' give less than 50 projects combined. Think someone might have already written what you need? yep.
Also, a great site: http://www.djangosnippets.org/, where I've learned a lot just by reading, and saved myself a lot of time, by extending ideas there.
And the development is active.
- User authentication is simple, and check google-code for various alterations on the theme.
- admin. This was what first made me decide on django. And now, new-forms admin is in trunk. This gives you a pretty nice CRUD interface for models in your app. In the app I've been working on, we have row _and_ field level permissions. We also need to let users edit the fields of other users stored in the database--but only certain fields, with which fields depending on the user viewing and the user being edited. This bit is more hacky than it should be, but quite simple.
My biggest gripe about the admin is that it's too complicated to use custom widgets or validation. Hopefully, this will change.
Oh, and it's too hard to have read_only privileges. (Yeah, I know the admin mantra).
- GIS: nuf said.
i18n, t9n. Anywhere there's some text to be displayed in the app, I wrap it in ugettext_lazy (aliased to _), and later, dump it and send it to someone who knows Chinese. When it returns, I make messages, and the app will show in English or Chinese depending on browser preferences. Simple.
docs/help: yeah, the docs may have trouble keeping up, especially with recent rate of change, but it's easy enough to find what you need, and the django official docs are pretty nice. And if you can handle the fact that most responses you'll get on #django will begin with "of course, ...", then it's a great place to get help.
ModelForms: I've just started using these, but, they've already saved me a lot of code.
There's a lot of other nice things, and a lot of django that I don't even know. I'd still consider myself a newb, but it's still possible to get sh*t done.