I'm a big fan of the Dan Brown books and I thought this book was a big improvement over The Lost Symbol, which they wisely IMO skipped to adapt Inferno instead.
Firstly I thought the locations were beautiful. I thought Tom Hanks, Felicity Jones and Irrfan Kahn were good. The book has lots of twists and reveals and some people might not like twists that mean what went before is turned on its head. I don't mind that and I thought the twists were handled well here.
I thought the score wasn't that good and was intrusive at times, something like this needs an orchestral score IMO. Some of the camera work and cuts were choppy with strange angles and sometimes too quick. I wouldn't say it came across as a TV movie though.
The lines are blurred throughout as to who's the good guys and who can be trusted and thats one of the aspects I liked about the book, but for me the shady organisation led by Irrfan Kahn wasn't explained quite well enough.
The ending is changed from the book, but I suppose it's a neater resolution for a film and less dark. It seemed that references to Dantes Inferno were cut down from what I remember in the book too.
Overall though I didn't think this was as bad as some reviews say. It's probably not as as good as Angels and Demons, but better than the Da Vinci Code adaptation (which I didn't enjoy that much). I'm glad I went to see it.