The other DrC and I saw Ron Howard's Angels and Demons on Saturday afternoon. We saw it in a heavily Mormon town in eastern Idaho, which may explain why the theater wasn't especially full.
The other DrC reports that her evangelical Christian girlfriend said something like "I'm not Catholic so why would I be interested in this film?" I didn't find being a non-Catholic was a problem in understanding the film.
We had been in Rome for a few days last fall and the film gives you a nice view of this amazing city, albeit much of it at high speed since the main characters are trying to identify four locations with Bernini statuary that are also significant to the Illuminati, an anti-church group of angry scientists. They only have four hours to do this which means there is much high-speed maneuvering through legendary Roman traffic aided by flashing lights and sirens. However, the film gives you a better view of the Sistine Chapel than you'll ever get as a tourist.
Rome has been the "headquarters" of the Catholic Church for most of the last two thousand years. As such it is very much a company town; there are churches everywhere and many priests, brothers, nuns and lay employees can be seen on its streets.
Does the film hang together plotwise? Only if you don't ask too many questions of it. There are many fortuitous coincidences some of which aid the bad guys and others which aid the good guys. The suspension of disbelief required by the film is considerable.
Elaborate things happen such that it is hard to see how the bad guys could have organized them in the available time. This particularly bothered the other DrC. There is a very nice plot twist right at the end of the film, which I will not reveal. Angels and Demons is a pleasant film but will not, I think, end up on your all-time favorite list.