I've found it really depends. I used the Advantage on my cats and dogs, it did nothing for my cat but when I put the flea collar on her, it worked great. The Advantage also did nothing for my dogs, one is over 100 lbs and the other around 30. My little one I put on the all in one pill (its new so I don't remember the name, starts with a T) and it works pretty good, it also treats heartworms, etc. When my daughter took her to be groomed she said she only had about 4 fleas on her which was pretty good. I think sometimes its the area that makes some of this stuff work and not the other. My daughter who grooms pets says the flea collars are better for cats and some smaller dogs.