I have been using DNN for a while and it was a bit tempermental during the initial experience with it , i was unfamiliar with the ASP.NET 2.0 technology and when i was recieving errors i was lost but DNN has a good community of users who were more than willing to help with questions,
DNN give me lots of functionality and quickly , it allows you to put up a web site really quickly securely and the administration is powerful, it has the skinning technology which separates the code from the presentation of the web site , so you can change the desgin of your site with one click its pretty sweet.