A good resource to compare them is http://www.djangopackages.com/grids/g/api/
Django-tastypie sure is the save choice right now.
Personally I’d advocate a look at django-rest-framework if you use django 1.3, because it uses the new class based views. djangopackages.com’s comparison page shows it has good participation and activity. And, wow, it sure has a nice browsable interface to the API.