Just finished it off, loved it! There was only one BS plot device, Ron accidentally getting parcletounge right, but it didn't matter enough to me. Everything else was put together very cleverly. I've heard complaints aout the the ending being too cookie cutter, but anything negative would have been to forced, contrived. It's a hero's tale, one that started off as a kids book, and still ,in my opinion, stayed one. Morals, lessons, good vs. evil, redemption.
Loved it and it was a great ending, it made me feel so bad for Snape regardless of him being a prick. Still, now you know why. It seems like he had almost NO happy memories in his life, sad, but still fought for love.