I just watched this film for the 2nd time last week. I loved the styling. It definitely had a european flair, like some italian filns of the 60's and 70's. Some close cropped shots of the characters, the lighting, the sent moments. Just beautiful, even if we are talking about an assassin movie.
I thought George Clooney was ok. Violante Placido burnt up the screen, she is that beautiful. And she seemed a great fit for her character.
I do have a penchant for movies about spies or assassins, and I will say this is one of my favourites.