One of Django applications I maintain is our internal tool used at SUSE used for managing incoming L3 requests. Recently request to add some API arose (read only for now). Looking at available solutions, I came to conclusion that django-piston should be the best choice for me.
Adding simple model based API with it is indeed quite simple, all basic information you need is written in getting started part of their documentation.
On the other side, things can never go without problems, so I was hit by well known bug. Fortunately fix exists, though it is not yet merged upstream. While digging so deep into problem anyway, I've submitted a request to include this patch in devel:languages:python OBS repo.