So, it looks like nobody has experienced a puncture flat with the Marathon Plus. I'll need to give it a try.

Today, something punctured my Conti Gatorskins. Probably glass (left a little slit in the tire), but I can't be positive since the offending object was not in the tire when I patched the tube. I seem to experience flats with the same amount of frequency with the supposedly flat resistant tires than ordinary tires, so I'm getting a little skeptical about the whole pitch. (BTW, I only get flats in wet weather, where even the best tires will have stuff stick to them more easily and have a greater opportunity to work their way to the tube.)