Saw the movie, was disappointed. Little seemed to happen in terms of plot, and the characters weren't very complex.
Read the first book. Didn't think it added much. Most of the added detail wasn't very significant, and the writing didn't "sing" to me.
The Wife then read all of them. She rather liked them, suggested I get back to them. Maybe someday.
In the meantime, I prefer Harry Potter And The Methods Of Rationality.
Plus Modern-Day Harry Potter: started Nov'2014