It is better than the other two brands I tried. My dogs still have ticks on them, though. This is not the Frontline I remember from ten years ago. Ten years ago Frontline killed all the fleas and ticks in the whole house! I am disapppointed but giving a positve review because it's better than the other alternatives.
I have only recently begun to use the Frontline Shield but it has had better results than 4 others that I have tried. It has really taken about 2 days before you see the effect. I also have to apply it before a month because my patio is frequented by neighborhood cats that do not have flea killers applied.