I personally loved the movie - I thought it was hilarious. I know what you mean about furthering the stereotypes of sororities but I wasn't offended by a single thing in it and I think they exaggerated everything enough so that you can tell they're just joking.
Oh and I am a DZ but I hadn't heard that there was any affiliation to us - I heard it was based on the DG's (VERY loosely based of course)