XSS With MongoDB / Django Forms
XSS is a Javascript vulnerability, it is unrelated to SQL injection.  To prevent XSS, you need to do the same sensitization, regardless of how your data is stored.
Based on its description, using that library and a CSRF token should be sufficient.
EDIT
While you do not need to worry about SQL injection with MongoDB. If you switch to a relational database, your application will no longer be secure.  Sanitizing against XSS injection offers no protection against SQL injection, which the library you mention will not do.
I am running a 100% NoSQL backend (MongoDB) and developing using Django. The application I am building has a lot of different forms, and for a variety of reasons, I am trying to avoid using Django.Forms because they are complicated and do not seem to be very flexible.
How worried do I need to be about XSS (as far as I can tell, it is not possible to get a SQL injection when you are using MongoDB)
Since most of my forms are being submitted via AJAX...is it enough to just use the Django CRSF tokens + an open source sanitizing lib (http://bitkickers.blogspot.com/2011/01/sanitize-html-with-beautiful-soup.html) with all incoming data?
What is the best solution to this problem that does not involve using cleaned_data with Django Forms?