Lots of fun. I wish there were more sources, but there's a fairly substantial bibliography in the back, so that's okay.
I like hearing the un-bowdlerized versions of these people. As with most very short, vignette-style biography compilations, though, it's a little sketchy on details. It's a little unfulfilling on its own. However, as something that jumpstarts continued reading - or, better, as a resource to jumpstart fiction-writing ideas! - it's amazing.
And, undetailed or not, it's a book about the scandalous lives of the saints before they were saints. What's better than that?