I did read the book ages ago now so I can't really remember if the following is true of that too, but the film spends far too much time (apart from the tourist stuff) on double-crossing espionage, deceit, counter-espionage from evil and good international organisations and the madness of a so-called visionary to destroy half the world for the good of humanity, which could have been energy spent with more focus on history and exposure of interesting paths, clues and trails.
The settings are interesting, regardless of the above, as location switches around (mostly) Italy and much can be enjoyed from that perspective. Direction from Ron Howard feels somewhere between good and functional, not breaking any records. Felicity Jones is far too cute to be true and the rest of the cast do their jobs admirably enough. There are dream sequences and hallucinations which take up far too much screen time but I suppose they're not irrelevant to the story.
It's a shame in a sense that the forward path is now not littered with interesting intrigue as it was in the earlier outings, but my guess is that it's about money. Maybe that's harsh. Maybe there's only so much thrill which can be drawn out from 'clues from the past' stuff. It's still a good film and enjoyable romp but I think it could have been better. I'd have to re-read the book to decide if the film has butchered the book or the series of books has indeed suffered an unhelpful twist in genre and focus. In the meantime, recommended with reservations.