Before buying that sign, here are places where I've found packages:
* My yard, helpfully hidden behind a flowerpot to fool thieves (and me)
* My neighbor's yard for some reason
* The sidewalk in front of my house
* Right in front of my outward-opening door, so that the package blocked the door from opening.
Ever since getting the sign (~6 months) all my packages have been dropped in exactly the right spot. I think the logos are important, because it draws the guy's attention.