It’s worth referring to djangopackages for these sorts of questions; http://djangopackages.com/grids/g/tagging/
You can see that you mentioned the two most popular with the others being hardly counted.
Personally I choose django-taggit. It’s simpler, maintained by Django core devs and it has more recently been updated. It’s also reassuring that the tox.ini in the django-taggit repository shows its tested against all the relevant python versions.
For me, django-tagging was bloated with more features than I would need but I understand they could be useful in some casses.
if tag cloud is what you concern, you can try django-taggit combined with django-taggit-templatetags. follow the instruction in the document in the second link, it’s easy to implement your own tag cloud with few lines of template. hope this helps.