I think it really centers around ease of use, amount of libraries, and community support. Django is widely adopted, has a long history of use, and is relatively easy to get started with. Performance is obviously important, but there are plenty of major websites using Django, so it can scale. This is a decent thread on that: http://www.quora.com/Django-web-framework/What-is-the-highes... .

Here is a great comparison of Go and Django: http://lincolnloop.com/blog/djangonaut-building-webapp-go-go... .

I personally have used Django for quite a few projects, and haven't had any "I wish I used a different framework/language" moments.