I've never done a "first" showing of a movie in my life and I was really happy I made this film my choice. It was great, I was riveted from beginning to end. This film did not have the "let's stop and explain some plot line from the last five movies, just in case you didn't see them" moments that I found annoying in the movies three and four.
The end was surprisingly not the tear-jerker I was expecting. I remember reading the book and balling my eyes out. I will say though I was VERY impressed with the subtleties of Alan Rickman's performance. He brought a dimension to Snape that for me was missing from the book and added a depth to his final scene that really pulled at my heart.