I had some pretty serious suspension of disbelief problems with this one, mostly having to do with the dynamics of three teenagers forced to keep each other company with no outside contact for eight months.
Rowling isn't very good at killing characters, or at least describing character deaths. She is even worse at describing battles; the big fight feels very much like, "people run around chaotically while our heroes..." She knew where things started, and where they ended, and didn't really care about the middle bit, even though she had to show the main characters experiencing it.
I found myself thinking again and again that "Philosopher's Stone" was written by an unemployed single mother who was running on dreams, and "Deathly Hallows" was written by a billionaire who had an obligation to fulfill. Perhaps this explains the ponderousness and lack of humor in "Hallows".
In the end, "Deathly Hallows" is a good book, and certainly worth the time I invested in it. But at the same time, I can't help but feel that the series was one book too long, and that "Half Blood Prince" and "Deathly Hallows" should have been collapsed into a single volume.
I will re-read the series sometime soonish, and see how I feel about such things when all of the details are fresh in my head.