Well, the bibs came in their plain brown wrapper. With shaking hands I tore open the package, found a way to pour my middle-aged frame into them, pulled on a jersey and slithered out the door for my first ride. Herewith, the report:
Comfort Factor: At first, the shoulders felt a bit constrained, but that feeling soon disappeared. As I began my ride, they seemed about as comfortable as other shorts, but as the ride progressed beyond 25 miles, they did seem more comfy than my old reliable cheepies.
Plumber Factor: I've seen a few riders showing more of their backside than anyone wanted to see. It was good to know that with bibs this is not gonna happen.
Heat Factor: In hot weather, the extra material around the middle and shoulders is somewhat noticable.
Porn Factor: As others have pointed out, there's absolutely no difference when you've got a jersey on. However, without a top, my wife thinks I look like an extra in a cheezy porn film.
Overall rating: Not the holy grail, but definitely some plusses. I'll still wear my non-bibs without complaint. If you're going to be seen in public wearing bibs, please wear a jersey.