As a teenager with a very teenage sense of humor, I found this movie very entertaining - the whole movie was laced with heaps of innuendo. It also contained a couple of rude/explicit British terms that I definitely wouldn't label as PG (maybe they figure the younger kids haven't found Urban Dictionary yet), so I was pretty shocked when I realized that it had slipped by with a PG rating.
That said, some parts of it were very well done, others were a bit awkward - but I feel like the awkward parts were the same ones that were awkward in the book. Luna, Draco, and Bellatrix are all (again) very well played! Definitely worth seeing.