First the good news-- the drama builds well, the storyline is engaging, and the overall writing quality and storytelling is good. The "treasure hunt" across Italy is quite well done and fairly suspenseful, though the fire in the church scene is a little hard to believe-- Really, the bad guy had time to run everybody out of the church, string the Cardinal up, stack up all those pews and start the fire? And nobody noticed or interrupted him? Really?
Now the bad news-- the characters are rather cartoonish, the dichotomy between church and science is far too black and white, and Mr. Brown's prejudices shine through far too often and in a rather garish fashion. More significantly, there are not one, not two, but at least three separate cliff-hanger endings and not one, not two, but three separate Hitchcockian surprise twists at the end. It's all too much, too convoluted, too over the top.
Oh, and Robert Langdon should've been dead many times over. Long before his completely improbable (I won't say impossible because, well, I guess it could happen) survival from the doomed helicopter, he should've been dead. Seriously, he's a Harvard professor who is a good swimmer against a trained killer. The hassassin had... three, four opportunities to kill Langdon?
The escape in the fountain was pretty good, the others... not buying it. And the whole Pope/Camerlengo back story "gotcha" twist at the end? Also not buying it. Suspension of disbelief only carries you so far, even with some great storytelling.
I won't say Angels and Demons was a complete waste, it had some fine moments and the philosophical questions raised are intriguing ones. But I really do think Dan Brown was being too clever by half. Oh, and he's kind of an academic version of a name dropper-- it would be interesting (or maybe not) to try and count the number of obscure references to academic peculiarities and topics mentioned or briefly described in Angels and Demons. Enough already!
This could have been a fine, intriguing suspenseful book without a good third of the "intrigue" and "surprise!" twists that Brown throws in. Instead, I found myself shaking my head and, on at least one occasion, groaning out loud as the tortured plot device was dragged into the storyline.
As a side note-- The da Vinci Code is better. It too suffers a little from Dan Brown's desire to be extremely clever, but it is less heavy-handed than Angels and Demons.