OK.. it's been 2 years and these tags have again risen to the top of "things to buy". One of my neighbors, who owns a specialty dog shop, put them on her coon hound and asked if I wanted them for my girls. I said, let's wait and see how they work on Trixie before I spend the money, and I just put Frontline on my girls anyway. She said she just put Frontline on her dog as well, so it will be difficult to check and see if they work at all. Her charge would be $58 for the two dogs that "supposedly" work for 4 months. In checking, I see about 50% good opinions and 50% "they are terrible".
I'm extremely skeptical.